Don't pin yaml2ics on (old) 0.1 version

0.1 does not yet understand the `also_on` tag, which we want to start using.

Signed-off-by: Kurt Garloff <kurt@garloff.de>

.github/workflows/yaml2ics.yml

@@ -19,7 +19,7 @@ jobs:
       run: |
         python -m pip install --upgrade pip
         pip install ics==0.8.0.dev0
-        pip install yaml2ics==0.1
+        pip install yaml2ics
         pip install pyyaml
     - name: Run communitycall.py
       run: |