Fix problems with env variables in Actions

.github/workflows/ubuntu.yml

@@ -5,8 +5,6 @@ jobs:
     runs-on: ubuntu-latest
     env:
       OF_URL: https://openframeworks.cc/versions/v0.11.0/of_v0.11.0_linux64gcc6_release.tar.gz
-      OF_ARCH_NAME: $(basename -- "$OF_URL")
-      OF_FILE_NAME: "${OF_ARCH_NAME%.*}"
     steps:
       - uses: actions/checkout@v2
         with:
@@ -14,9 +12,13 @@ jobs:
       - run: mkdir .ofxPiMapper
       - run: mv ./* .ofxPiMapper/
       - run: wget ${OF_URL} --tries=10
-      - run: tar -xvf ${OF_ARCH_NAME}
-      - run: rm ${OF_ARCH_NAME}
-      - run: mv ${OF_FILE_NAME} openFrameworks
+      - run: |
+          echo "Unarchive openFrameworks"
+          OF_ARCHIVE_NAME=$(basename -- "$OF_URL")
+          tar -xvf ${OF_ARCHIVE_NAME}
+          rm ${OF_ARCHIVE_NAME}
+          OF_EXTRACT_NAME="${OF_ARCHIVE_NAME%.*}"
+          mv ${OF_EXTRACT_NAME} openFrameworks
       - run: mv .ofxPiMapper openFrameworks/addons/ofxPiMapper
       - run: |
           echo "Install openFrameworks Dependencies"