.forgejo/workflows: Do not upload artifact on missing secrets

Forgejo does not give access to the repository secrets to forked
repositories, which means it is not possible to upload artifacts.
As a workaround, skip the complete step.

.forgejo/workflows/build-3rdparty.yml

@@ -25,7 +25,13 @@ jobs:
         run: tar -czf 3rdparty-$(git describe --tags).tar.gz 3rdParty/
         working-directory: /src/packaging/3rdParty-devel/build
       - name: Upload third-party libraries
-        run: upload-artifact 3rdparty-$(git describe --tags).tar.gz
+        run: |
+          if [ $USERNAME ]
+          then
+            upload-artifact 3rdparty-$(git describe --tags).tar.gz
+          else
+            echo "Skipping due to missing secrets" >&2
+          fi
         working-directory: /src/packaging/3rdParty-devel/build
         env:
           URL: ${{ vars.STORE_URL }}

.forgejo/workflows/build-deb.yml

@@ -33,7 +33,13 @@ jobs:
         run: cpack -G DEB
         working-directory: /src/build
       - name: Upload Debian package
-        run: upload-artifact -d ${{ matrix.image }} *.deb
+        run: |
+          if [ $USERNAME ]
+          then
+            upload-artifact -d ${{ matrix.image }} *.deb
+          else
+            echo "Skipping due to missing secrets" >&2
+          fi
         working-directory: /src/build
         env:
           URL: ${{ vars.STORE_URL }}

.forgejo/workflows/build-w64-mingw32.yml

@@ -31,7 +31,13 @@ jobs:
         run: cpack -G NSIS
         working-directory: src/build
       - name: Upload installer
-        run: upload-artifact *.exe
+        run: |
+          if [ $USERNAME ]
+          then
+            upload-artifact *.exe
+          else
+            echo "Skipping due to missing secrets" >&2
+          fi
         working-directory: src/build
         env:
           URL: ${{ vars.STORE_URL }}