Add numpy and other Python pkgs to CI (#585)

This adds numpy and other Python packages to GitHub Actions using apt.

It also increases minimal required success rate to 80% because with Python dependencies in place we are currently getting 82-84% success rate.

.github/workflows/apt.txt

@@ -13,6 +13,10 @@ libpng-dev
 libproj-dev
 libreadline-dev
 libzstd-dev
+python3-dateutil
+python3-numpy
+python3-ply
 python3-six
+python3-termcolor
 sqlite3
 zlib1g-dev

.github/workflows/test_thorough.sh

@@ -11,4 +11,4 @@ grass79 --tmp-location XY --exec \
 grass79 --tmp-location XY --exec \
     python3 -m grass.gunittest.main \
         --grassdata $HOME --location nc_spm_full_v2alpha2 --location-type nc \
-        --min-success 50
+        --min-success 80