set pint version min to 0.21.1

Author: dylanwal

.github/workflows/test.yml

@@ -10,7 +10,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: ["3.8", "3.10", "3.11", "3.12"]
+        python-version: ["3.8", "3.11", "3.12"]
 
     steps:
       - uses: actions/checkout@v3