.github: speed up release job, and support for setting pre-release

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

.github/workflows/release.yml

@@ -10,12 +10,24 @@ jobs:
     name: Build and upload release tarball
     if: startsWith(github.ref, 'refs/tags/')
     runs-on: ubuntu-latest
+    env:
+      MAKEFLAGS: -j3
     steps:
       - uses: actions/checkout@v3
       - name: Installing dependencies ...
         run: |
           sudo apt-get -y update
           sudo apt-get -y install pkg-config jq libuev-dev libite-dev
+      - name: Setting release variables ...
+        id: build
+        run: |
+          ver=${GITHUB_REF#refs/tags/}
+          echo "ver=${ver}" >> $GITHUB_OUTPUT
+          if echo $ver | grep -qE '[0-9.]+(-alpha|-beta|-rc)[0-9]*'; then
+            echo "pre=true"  >> $GITHUB_OUTPUT
+          else
+            echo "pre=false" >> $GITHUB_OUTPUT
+          fi
       - name: Creating Makefiles ...
         run: |
           ./autogen.sh
@@ -36,5 +48,6 @@ jobs:
       - uses: ncipollo/release-action@v1
         with:
           name: Finit v${{ github.ref_name }}
+          prerelease: ${{ needs.build.outputs.pre }}
           bodyFile: "release.md"
           artifacts: "artifacts/*"