Addon Manager: Show package dependencies

src/Mod/AddonManager/PythonDependencyUpdateDialog.ui

@@ -46,8 +46,11 @@
       <bool>true</bool>
      </property>
      <property name="columnCount">
-      <number>4</number>
+      <number>5</number>
      </property>
+     <attribute name="horizontalHeaderStretchLastSection">
+      <bool>true</bool>
+     </attribute>
      <attribute name="verticalHeaderVisible">
       <bool>false</bool>
      </attribute>
@@ -66,6 +69,11 @@
        <string>Available version</string>
       </property>
      </column>
+     <column>
+      <property name="text">
+       <string>Used by</string>
+      </property>
+     </column>
      <column>
       <property name="text">
        <string/>
@@ -73,6 +81,16 @@
      </column>
     </widget>
    </item>
+   <item>
+    <widget class="QLabel" name="label_2">
+     <property name="text">
+      <string>An asterisk (*) in the &quot;Used by&quot; column indicates an optional dependency. Note that Used by only records direct imports in the Addon. Other Python packages that those packages depend upon may have been installed as well.</string>
+     </property>
+     <property name="wordWrap">
+      <bool>true</bool>
+     </property>
+    </widget>
+   </item>
    <item>
     <layout class="QHBoxLayout" name="horizontalLayout">
      <item>