Remove PYTHONWARNINGS from workflow environment

This used to be set in order to silence some deprecation warnings,
but now we want these warnings to appear in the logs, to address
them as soon as we see them.

Author: molinav

.github/workflows/build.yml

@@ -67,7 +67,6 @@ jobs:
               LD_LIBRARY_PATH="/project/packages/basemap/extern/lib"
               PIP_PREFER_BINARY=1
               PYTHONUNBUFFERED=1
-              PYTHONWARNINGS="ignore:DEPRECATION"
 
           - os: windows-latest
             before_all: >-
@@ -83,7 +82,6 @@ jobs:
               GEOS_DIR="D:/a/basemap/basemap/packages/basemap/extern"
               PIP_PREFER_BINARY=1
               PYTHONUNBUFFERED=1
-              PYTHONWARNINGS="ignore:DEPRECATION"
 
     runs-on: ${{ matrix.os }}
     steps: