Merge branch 'master' of https://github.com/matplotlib/mplfinance

Author: Daniel Goldfarb

.github/workflows/mplfinance_checks.yml

@@ -2,7 +2,7 @@ name: mplfinance Checks
 on: [ workflow_dispatch, pull_request ]
 jobs:
   Regression_Tests:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     strategy:
       matrix:
         python-version: [3.6, 3.7, 3.8, 3.9]
@@ -46,7 +46,7 @@ jobs:
       - run: echo "This job's status is ${{ job.status }}."
 
   Pull_Request_Updates_Version:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     if: github.event_name == 'pull_request'
     steps:
       - name: Check out repository code