Add CI for Ubuntu 22.04

Tests currently fail on Ubuntu 22.04 because oscrypto doesn't properly
support OpenSSL 3. Will hopefully be fixed soon.

.github/workflows/main.yml

@@ -5,7 +5,7 @@ on:
     branches: [ master ]
 
 jobs: 
-  build-linux:
+  build:
     runs-on: ubuntu-latest
     steps: 
       - uses: actions/checkout@v2
@@ -25,8 +25,8 @@ jobs:
           path: |
             calibre-plugin.zip
     
-  test-linux:
-    runs-on: ubuntu-latest
+  test-ubuntu-2004:
+    runs-on: ubuntu-20.04
     steps: 
       - uses: actions/checkout@v2
 
@@ -47,3 +47,25 @@ jobs:
         run: |
           cd tests && PYTHONWARNINGS=ignore python2 ./main.py && cd ..
 
+  test-ubuntu-2204:
+    runs-on: ubuntu-22.04
+    steps: 
+      - uses: actions/checkout@v2
+
+      - name: Install dependencies
+        run: |
+          # Require cryptography >= 3.1 because in 3.0 and below, the backend param in load_key_and_certificates was still required.
+          pip3 install freezegun lxml pycryptodome rsa oscrypto "cryptography>=3.1"
+          # Install Python2 stuff
+          curl https://bootstrap.pypa.io/pip/2.7/get-pip.py --output get-pip.py
+          sudo apt install python2
+          python2 get-pip.py
+          pip2 install freezegun mock lxml pycryptodome "rsa<=4.3" oscrypto cryptography==3.1
+
+      - name: Run tests (Python 3)
+        run: |
+          cd tests && python3 ./main.py && cd ..
+
+      - name: Run tests (Python 2)
+        run: |
+          cd tests && PYTHONWARNINGS=ignore python2 ./main.py && cd ..