Github actions: Fix deprecation warning for set-output

Use of `::set-output` is deprecated. See:

https://github.blog/changelog/2022-10-11-github-actions-deprecating-save-state-and-set-output-commands

.github/workflows/android_release.yml

@@ -68,10 +68,7 @@ jobs:
 
       - name: Prepare ccache timestamp
         id: ccache_cache_timestamp
-        shell: cmake -P {0}
-        run: |
-          string(TIMESTAMP current_date "%Y-%m-%d-%H;%M;%S" UTC)
-          message("::set-output name=timestamp::${current_date}")
+        run: echo "name=timestamp::$(date --utc +'%Y-%m-%d-%H\;%M\;%S')" >> $GITHUB_OUTPUT
 
       - name: ccache cache files
         uses: actions/cache@v3

.github/workflows/linux_debug.yml

@@ -51,10 +51,7 @@ jobs:
 
       - name: Prepare ccache timestamp
         id: ccache_cache_timestamp
-        shell: cmake -P {0}
-        run: |
-          string(TIMESTAMP current_date "%Y-%m-%d-%H;%M;%S" UTC)
-          message("::set-output name=timestamp::${current_date}")
+        run: echo "name=timestamp::$(date --utc +'%Y-%m-%d-%H\;%M\;%S')" >> $GITHUB_OUTPUT
 
       - name: ccache cache files
         uses: actions/cache@v3

.github/workflows/linux_release.yml

@@ -60,10 +60,7 @@ jobs:
 
       - name: Prepare ccache timestamp
         id: ccache_cache_timestamp
-        shell: cmake -P {0}
-        run: |
-          string(TIMESTAMP current_date "%Y-%m-%d-%H;%M;%S" UTC)
-          message("::set-output name=timestamp::${current_date}")
+        run: echo "name=timestamp::$(date --utc +'%Y-%m-%d-%H\;%M\;%S')" >> $GITHUB_OUTPUT
 
       - name: ccache cache files
         uses: actions/cache@v3

.github/workflows/macos_release.yml

@@ -59,10 +59,7 @@ jobs:
 
       - name: Prepare ccache timestamp
         id: ccache_cache_timestamp
-        shell: cmake -P {0}
-        run: |
-          string(TIMESTAMP current_date "%Y-%m-%d-%H;%M;%S" UTC)
-          message("::set-output name=timestamp::${current_date}")
+        run: echo "name=timestamp::$(date --utc +'%Y-%m-%d-%H\;%M\;%S')" >> $GITHUB_OUTPUT
 
       - name: ccache cache files
         uses: actions/cache@v3