Install QtApng dependency

.github/workflows/cmake.yml

@@ -45,6 +45,13 @@ jobs:
     - name: Install Qt5
       run: sudo apt update -y && sudo apt install -y qt5-default
 
+    - name: Install QtApng
+      run: |
+        git clone https://github.com/Skycoder42/QtApng
+        cd QtApng
+        qmake
+        sudo make install
+
     - name: Create Build Environment
       # Some projects don't allow in-source building, so create a separate build directory
       # We'll use this as our working directory for all subsequent commands