rename matrix session to "gha_matrix"

Author: joshuadavidthomas

.github/workflows/test.yml

@@ -34,7 +34,7 @@ jobs:
 
       - id: set-matrix
         run: |
-          python -m nox --session "matrix"
+          python -m nox --session "gha_matrix"
 
   test:
     name: Python ${{ matrix.python-version }}, Django ${{ matrix.django-version }}

noxfile.py

@@ -116,7 +116,7 @@ def mypy(session):
 
 
 @nox.session
-def matrix(session):
+def gha_matrix(session):
     sessions_json = session.run("nox", "-l", "--json", silent=True)
     sessions = json.loads(sessions_json)
     matrix = {