build: use latest python

Author: sgratzl

.github/workflows/ci.yaml

@@ -24,7 +24,7 @@ jobs:
             ${{ runner.os }}-conda6-
       - uses: conda-incubator/setup-miniconda@v2
         with:
-          python-version: 3.7
+          python-version: 3.9
           mamba-version: "*"
           channels: conda-forge,defaults
           channel-priority: true

environment.yml

@@ -4,7 +4,7 @@ channels:
   - defaults
 dependencies:
   - gdal
-  - python=3.8.7
+  - python=3.9.1
   - pip
   - r-base=3.6.3
   - glib