Actions: Remove python-dep

We shouldn't lock down to old python version.

Signed-off-by: Benjamin Copeland <ben.copeland@linaro.org>

Author: bhcopeland

.github/workflows/docs.yml

@@ -5,9 +5,6 @@ on: [push, pull_request]
 jobs:
   build:
     runs-on: ubuntu-latest
-    strategy:
-      matrix:
-        python-version: [3.7]
 
     steps:
       - uses: actions/checkout@v2

.github/workflows/test-plans-pipeline.yml

@@ -5,9 +5,6 @@ on: [push, pull_request]
 jobs:
   build:
     runs-on: ubuntu-latest
-    strategy:
-      matrix:
-        python-version: [3.6]
 
     steps:
       - uses: actions/checkout@v2