treat workflow input as string

see https://github.com/actions/runner/issues/1483

.github/workflows/debian.yml

@@ -105,7 +105,7 @@ jobs:
             cryptomator_*_amd64.deb
             cryptomator_*.asc
       - name: Run dput to beta repo
-        if: startsWith(github.ref, 'refs/tags/') || github.event.inputs.dput
+        if: startsWith(github.ref, 'refs/tags/') || github.event.inputs.dput == 'true'
         run: dput ppa:sebastian-stenzel/cryptomator-beta cryptomator_*_source.changes
       - name: Publish Debian package on GitHub Releases
         if: startsWith(github.ref, 'refs/tags/')