Speedup CI build somewhat (#171)

* github action: set CI: true

* github action: only use `setup-graalvm` action on windows

this is only needed because it makes some windows development stuff available. figure out how bleep can download it itself

.github/workflows/build.yml

@@ -29,6 +29,8 @@ jobs:
         run: cs install --channel channel bleep --verbose
 
       - name: Run tests
+        env:
+          CI: true
         run: |
           bleep generate-resources
           bleep test
@@ -54,7 +56,9 @@ jobs:
       - uses: actions/checkout@v2
         with:
           submodules: recursive
+      # todo: this is only needed because it makes some windows development stuff available. figure out how bleep can download it itself
       - uses: graalvm/setup-graalvm@v1
+        if: runner.os == 'Windows'
         with:
           version: '22.1.0'
           java-version: '17'
@@ -74,6 +78,8 @@ jobs:
         if: runner.os != 'Windows'
 
       - name: Test binary after build (non-windows)
+        env:
+          CI: true
         run: ./${{ matrix.file_name }} --ignore-version-in-build-file test --no-color jvm213
         if: runner.os != 'Windows'
 
@@ -93,6 +99,8 @@ jobs:
 
       - name: Test binary after build (windows)
         shell: cmd
+        env:
+          CI: true
         # todo: fix tests on windows
         run: .\${{ matrix.file_name }} --ignore-version-in-build-file compile --no-color jvm213
         if: runner.os == 'Windows'