pin planemo

As a workaround for:

```
AttributeError: 'CondaTarget' object has no attribute 'package_name'
```

and install planemo in PR job

.github/workflows/monitor.yaml

@@ -7,6 +7,7 @@ on:
     - cron: "0 0 * * *"
 env:
   GITHUB_USER: dockerhub-toolshed
+  PLANEMO_VERSION: planemo=0.75.18
 jobs:
   monitor:
     name: Run planemo monitor
@@ -24,6 +25,8 @@ jobs:
       - uses: actions/setup-python@v1
         with:
           python-version: ${{ matrix.python-version }}
+      - name: Install planemo
+        run: pip install PyGithub ${{ env.PLANEMO_VERSION }}
       - name: Set github user
         run: |
           git config --global user.email "[email protected]"

monitor.sh

@@ -1,16 +1,5 @@
 #!/bin/bash
 
-: ${PLANEMO_TARGET:="planemo==0.74.19"}
-
-if [ ! -f .venv ]; then
-    python -m venv .venv
-    . .venv/bin/activate
-    pip install -U pip
-    pip install PyGithub
-    git clone --recursive https://github.com/galaxyproject/planemo && pip install planemo/
-    # pip install "$PLANEMO_TARGET"
-fi
-
 planemo conda_init
 
 sort -R $1 | while read repository