Use Python 3.8 as minimal version (which should work on Ubuntu 20.04)

Author: thomaskrause

.github/workflows/deploy.yml

@@ -4,14 +4,14 @@ on: push
 jobs:
   deploy:
     name: Deploy graphANNIS package
-    runs-on: ubuntu-22.04
+    runs-on: ubuntu-20.04
     # Only run Job on tagged commits that start with "v"
     if: startsWith(github.ref, 'refs/tags/v')
     steps:
     - name: Setup Python
       uses: actions/setup-python@v2
       with:
-        python-version: '3.6'
+        python-version: '3.8'
     - name: Checkout
       uses: actions/checkout@v1
     - name: Install dependencies

.github/workflows/test.yml

@@ -4,12 +4,12 @@ on: push
 jobs:
   test:
     name: Execute all automated tests
-    runs-on: ubuntu-22.04
+    runs-on: ubuntu-20.04
     steps:
     - name: Setup Python
       uses: actions/setup-python@v2
       with:
-        python-version: '3.6'
+        python-version: '3.8'
     - name: Checkout
       uses: actions/checkout@v1
     - name: Chache pip dependencies

CHANGELOG.md

@@ -6,6 +6,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Changed
 
 - Update to graphANNIS 2.4.8.
+- Changed minimal Python version to 3.8
 
 ## [2.1.0] - 2022-06-01