Completely drop Python 3.8 and 3.9 testing support

These versions of Python are EOL and pose incompatibility issues in the
Conda environments.

Author: popescu-v

.github/workflows/conda.yml

@@ -62,7 +62,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ['3.8', '3.9', '3.10', '3.11', '3.12', '3.13', '3.14']
+        python-version: ['3.10', '3.11', '3.12', '3.13', '3.14']
         env:
           - {os: ubuntu-22.04, json-image: '{"image": "ubuntu:20.04"}'}
           - {os: ubuntu-22.04, json-image: '{"image": null}'}

.github/workflows/dev-docker.yml

@@ -4,7 +4,7 @@ env:
   DEFAULT_KHIOPS_REVISION: 11.0.0-rc.2
   DEFAULT_IMAGE_INCREMENT: 0
   DEFAULT_SERVER_REVISION: main
-  DEFAULT_PYTHON_VERSIONS: 3.8 3.9 3.10 3.11 3.12 3.13 3.14
+  DEFAULT_PYTHON_VERSIONS: 3.10 3.11 3.12 3.13 3.14
   DEFAULT_KHIOPS_GCS_DRIVER_REVISION: 0.0.14
   DEFAULT_KHIOPS_S3_DRIVER_REVISION: 0.0.14
 on:
@@ -30,7 +30,7 @@ on:
         description: Set as 'latest'
       python-versions:
         type: string
-        default: 3.8 3.9 3.10 3.11 3.12 3.13 3.14
+        default: 3.10 3.11 3.12 3.13 3.14
         description: Python versions to support
       server-revision:
         type: string