Update pythonapp.yml

Adding on workflow_dispatch, hopefully enabling the possibility to run the workflow manually.
Moved up to from python 3.7 to 3.10

.github/workflows/pythonapp.yml

@@ -1,6 +1,6 @@
 name: Python application
 
-on: [push]
+on: [push, workflow_dispatch]
 
 jobs:
   build:
@@ -9,10 +9,10 @@ jobs:
 
     steps:
     - uses: actions/checkout@v1
-    - name: Set up Python 3.7
+    - name: Set up Python 3.10
       uses: actions/setup-python@v1
       with:
-        python-version: 3.7
+        python-version: 3.10
     - name: Install dependencies
       run: |
         python -m pip install --upgrade pip