CI: remove unused Python version checks.

References: commit fc43da8

.github/workflows/ci.yml

@@ -63,16 +63,6 @@ jobs:
       run: |
         python -m pip install pytest
         python -m pytest --verbose
-      if:
-        matrix.python != '3.3' &&
-        matrix.python != '3.4'
-    - name: run tests
-      run: |
-        python -m pip install nose
-        python -m nose --verbose
-      if:
-        matrix.python == '3.3' ||
-        matrix.python == '3.4'
     - name: run pycodestyle
       run: |
         pip install pycodestyle
@@ -83,17 +73,12 @@ jobs:
         python -m pydiatra -v .
     - name: run pyflakes
       run: |
-        pyflakes=pyflakes
-        if [[ ${{matrix.python}} = 3.3 ]]; then pyflakes+='<2'; fi
-        python -m pip install $pyflakes
+        python -m pip install pyflakes
         python -m pyflakes .
     - name: run pylint
       run: |
         pip install pylint
         private/run-pylint
-      if:
-        matrix.python != '3.3' &&
-        matrix.python != '3.4'
     - name: check changelog syntax
       run:
         dpkg-parsechangelog -ldoc/changelog --all 2>&1 >/dev/null | { ! grep .; }