ci(GHA): replaced set-output with GITHUB_OUTPUT (#32)

Reason: deprecated, will be removed in 2023-05-31.

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

Command: grep -R -l "::set-output" . | xargs -n 1 sed -E -i '' 's/"?::set-output name=([^:]+)::([^"]+)"?$/"\1=\2" >> $GITHUB_OUTPUT/g'

.github/workflows/server.yml

@@ -35,7 +35,7 @@ jobs:
           password: ${{ secrets.CR_PAT }}
       - name: Determine image tag
         id: imagetag
-        run: echo "::set-output name=value::$(if [ $REF_TYPE = tag ]; then echo $REF_NAME | sed 's/server-//g'; elif [ $REF_NAME = master ]; then echo latest; else echo $REF_NAME; fi)"
+        run: echo "value=$(if [ $REF_TYPE = tag ]; then echo $REF_NAME | sed 's/server-//g'; elif [ $REF_NAME = master ]; then echo latest; else echo $REF_NAME; fi)" >> $GITHUB_OUTPUT
         env:
           REF_NAME: ${{ github.ref_name }}
           REF_TYPE: ${{ github.ref_type }}