Add release zsync update files to continuous

As there will be releases 1.7.1, 1.7.2 etc., storing zsync in release
asset doesn't make sense (further version won't update previous update
information). Thus store this in continuous release assets - update
channel "release" was introduced aside to existing "continuous".

.github/scripts/environment.sh

@@ -3,6 +3,7 @@
 if expr $GITHUB_REF : 'refs/heads/release/'; then
   VERSION=${GITHUB_REF#refs/heads/release/}
   TAG=v$VERSION
+  CHANNEL=release
 elif [ $GITHUB_REF = 'refs/heads/ndi-build' ]; then
   VERSION=ndi
   TAG=$VERSION
@@ -11,7 +12,12 @@ else
   TAG=$VERSION
 fi
 
-export VERSION TAG
+if [ -z ${CHANNEL-""} ]; then
+        CHANNEL=$VERSION
+fi
 
-echo "VERSION=$VERSION" >> $GITHUB_ENV
+export CHANNEL TAG VERSION
+
+echo "CHANNEL=$CHANNEL" >> $GITHUB_ENV
 echo "TAG=$TAG" >> $GITHUB_ENV
+echo "VERSION=$VERSION" >> $GITHUB_ENV

.github/workflows/ccpp.yml

@@ -100,7 +100,7 @@ jobs:
     - name: check libc/libstdc++ ABI
       run: .github/scripts/Linux/check_abi.sh 2.27 3.4.22 1.3.9 bin/* lib/ultragrid/*
     - name: Create AppImage
-      run: APPIMAGE=`data/scripts/Linux-AppImage/create-appimage.sh https://github.com/$GITHUB_REPOSITORY/releases/download/$TAG/UltraGrid-$VERSION-x86_64.AppImage.zsync` && mv $APPIMAGE UltraGrid-$VERSION-x86_64.AppImage
+      run: APPIMAGE=`data/scripts/Linux-AppImage/create-appimage.sh https://github.com/$GITHUB_REPOSITORY/releases/download/continuous/UltraGrid-$CHANNEL-x86_64.AppImage.zsync` && mv $APPIMAGE UltraGrid-$VERSION-x86_64.AppImage
     - name: Check AppImage
       run: |
         docker build -f .github/scripts/Linux/utils/Dockerfile.ubuntu -t aitest-ubuntu .
@@ -124,8 +124,8 @@ jobs:
         GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
       run: |
         sudo apt install jq zsync
-        zsyncmake -C UltraGrid-$VERSION-x86_64.AppImage
-        .github/scripts/replace-asset.sh $TAG UltraGrid-$VERSION-x86_64.AppImage.zsync application/x-zsync AppImage%20zsync
+        zsyncmake -C -u https://github.com/$GITHUB_REPOSITORY/releases/download/$TAG/UltraGrid-$VERSION-x86_64.AppImage -o UltraGrid-$CHANNEL-x86_64.AppImage.zsync UltraGrid-$VERSION-x86_64.AppImage
+        .github/scripts/replace-asset.sh continuous UltraGrid-$CHANNEL-x86_64.AppImage.zsync application/x-zsync AppImage%20${CHANNEL}%20zsync
         .github/scripts/replace-asset.sh $TAG UltraGrid-$VERSION-x86_64.AppImage application/x-appimage Linux%20build
     - name: Upload Build
       if: steps.upload-ndi.conclusion == 'skipped' && steps.upload-release.conclusion == 'skipped'