Quick CI Fix

The last patch removed the remaining requirements.txt as it was leftover
from the pipenv transition. However, this broke the CI as setup-python's
cache is set to pip which depends upon the hash of a requirements.txt.
This implements a quick fix by setting the cache dependency path (used
for the hash) to the Pipfile.lock. This is not optimal since the pipenv
deps don't get cached (based on my testing), but they weren't before
either (as far as I can tell). More testing is needed, but this should
get the CI green.

Author: boomanaiden154

.github/workflows/main.yml

@@ -53,6 +53,7 @@ jobs:
         with:
           python-version: ${{ matrix.python-version }}
           cache: 'pip'
+          cache-dependency-path: Pipfile.lock
       - name: Install Python, no cache
         if: needs.Envvars.outputs.do_cache == '0'
         uses: actions/setup-python@v4