Update adwaita-icon minimum version, sync with 3.20 version

debian/control

@@ -229,7 +229,7 @@ Package: lubuntu-icon-theme
 Architecture: all
 Depends: hicolor-icon-theme,
          ${misc:Depends}
-Provides: adwaita-icon-theme (= 3.18),
+Provides: adwaita-icon-theme (= 3.20),
           adwaita-icon-theme-full,
           gnome-icon-theme,
           gnome-icon-theme-symbolic,

src/usr/share/icons/Lubuntu/imported-Adwaita/scalable/application-x-addon-symbolic.svg

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<!-- Created with Inkscape (http://www.inkscape.org/) -->
+<svg id="svg7384" xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns="http://www.w3.org/2000/svg" xmlns:osb="http://www.openswatchbook.org/uri/2009/osb" height="16" width="16" version="1.1" xmlns:cc="http://creativecommons.org/ns#" xmlns:dc="http://purl.org/dc/elements/1.1/">
+ <metadata id="metadata90">
+  <rdf:RDF>
+   <cc:Work rdf:about="">
+    <dc:format>image/svg+xml</dc:format>
+    <dc:type rdf:resource="http://purl.org/dc/dcmitype/StillImage"/>
+    <dc:title>Gnome Symbolic Icon Theme</dc:title>
+   </cc:Work>
+  </rdf:RDF>
+ </metadata>
+ <title id="title9167">Gnome Symbolic Icon Theme</title>
+ <g id="layer14" transform="translate(-601 -321)">
+  <path id="rect6917" style="color-rendering:auto;color:#000000;isolation:auto;mix-blend-mode:normal;shape-rendering:auto;solid-color:#000000;image-rendering:auto;enable-background:new;fill:#bebebe" d="m607.5 322c-0.831 0-1.5 0.669-1.5 1.5v1.5h-3c-0.554 0-1 0.446-1 1v3h1.5c0.831 0 1.5 0.669 1.5 1.5s-0.669 1.5-1.5 1.5h-1.5v3c0 0.554 0.446 1 1 1h3v-1.5c0-0.831 0.669-1.5 1.5-1.5s1.5 0.669 1.5 1.5v1.5h3c0.554 0 1-0.446 1-1v-3h1.5c0.831 0 1.5-0.669 1.5-1.5s-0.669-1.5-1.5-1.5h-1.5v-3c0-0.554-0.446-1-1-1h-3v-1.5c0-0.831-0.669-1.5-1.5-1.5z"/>
+ </g>
+</svg>

src/usr/share/icons/Lubuntu/imported-Adwaita/scalable/document-edit-symbolic.svg

@@ -0,0 +1,18 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<!-- Created with Inkscape (http://www.inkscape.org/) -->
+<svg id="svg7384" xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns="http://www.w3.org/2000/svg" xmlns:osb="http://www.openswatchbook.org/uri/2009/osb" height="16" width="16" version="1.1" xmlns:cc="http://creativecommons.org/ns#" xmlns:dc="http://purl.org/dc/elements/1.1/">
+ <metadata id="metadata90">
+  <rdf:RDF>
+   <cc:Work rdf:about="">
+    <dc:format>image/svg+xml</dc:format>
+    <dc:type rdf:resource="http://purl.org/dc/dcmitype/StillImage"/>
+    <dc:title>Gnome Symbolic Icon Theme</dc:title>
+   </cc:Work>
+  </rdf:RDF>
+ </metadata>
+ <title id="title9167">Gnome Symbolic Icon Theme</title>
+ <g id="layer12" transform="translate(-400.98 -766.99)">
+  <path id="path13107" style="fill:#bebebe;fill-rule:evenodd" d="m403.66 777.28 5.8493-5.8508c1 0 2.9998 1.9998 2.9998 2.9998l-5.8289 5.8731-4.0268 1.0718z"/>
+  <path id="path13109" style="enable-background:new;fill:#bebebe" d="m410.23 770.71c1 0 3.0605 2.0606 3.0605 3.0606l1.7069-1.7068c0-1-1.81-3.06-3.06-3.06z"/>
+ </g>
+</svg>

src/usr/share/icons/Lubuntu/imported-Adwaita/scalable/view-app-grid-symbolic.svg

@@ -0,0 +1,25 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<!-- Created with Inkscape (http://www.inkscape.org/) -->
+<svg id="svg7384" xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns="http://www.w3.org/2000/svg" xmlns:osb="http://www.openswatchbook.org/uri/2009/osb" height="16" width="16" version="1.1" xmlns:cc="http://creativecommons.org/ns#" xmlns:dc="http://purl.org/dc/elements/1.1/">
+ <metadata id="metadata90">
+  <rdf:RDF>
+   <cc:Work rdf:about="">
+    <dc:format>image/svg+xml</dc:format>
+    <dc:type rdf:resource="http://purl.org/dc/dcmitype/StillImage"/>
+    <dc:title>Gnome Symbolic Icon Theme</dc:title>
+   </cc:Work>
+  </rdf:RDF>
+ </metadata>
+ <title id="title9167">Gnome Symbolic Icon Theme</title>
+ <g id="layer12" transform="translate(-61 -887)">
+  <rect id="rect9843" style="color:#000000;enable-background:new;fill:#bebebe" rx="1" ry="1" height="2" width="2" y="890" x="64"/>
+  <rect id="rect9833" style="color:#000000;enable-background:new;fill:#bebebe" rx="1" ry="1" height="2" width="2" y="890" x="68"/>
+  <rect id="rect9835" style="color:#000000;enable-background:new;fill:#bebebe" rx="1" ry="1" height="2" width="2" y="890" x="72"/>
+  <rect id="rect9837" style="color:#000000;enable-background:new;fill:#bebebe" rx="1" ry="1" height="2" width="2" y="894" x="64"/>
+  <rect id="rect9839" style="color:#000000;enable-background:new;fill:#bebebe" rx="1" ry="1" height="2" width="2" y="894" x="68"/>
+  <rect id="rect9841" style="color:#000000;enable-background:new;fill:#bebebe" rx="1" ry="1" height="2" width="2" y="894" x="72"/>
+  <rect id="rect9845" style="color:#000000;enable-background:new;fill:#bebebe" rx="1" ry="1" height="2" width="2" y="898" x="64"/>
+  <rect id="rect9847" style="color:#000000;enable-background:new;fill:#bebebe" rx="1" ry="1" height="2" width="2" y="898" x="68"/>
+  <rect id="rect9849" style="color:#000000;enable-background:new;fill:#bebebe" rx="1" ry="1" height="2" width="2" y="898" x="72"/>
+ </g>
+</svg>