testing/gdal: use python3

7 jobs for !681 with gdal in 29 minutes and 38 seconds (queued for 1 second)
detached
Status Job ID Name Coverage
  Lint
passed #7163
docker-alpine x86_64
lint

00:00:31

 
  Build
passed #7168
docker-alpine ci-build aarch64
build-aarch64

00:06:09

passed #7169
docker-alpine ci-build armv7
build-armv7

00:05:39

passed #7167
docker-alpine ci-build ppc64le
build-ppc64le

00:04:30

passed #7166
docker-alpine ci-build s390x
build-s390x

00:07:40

passed #7165
docker-alpine ci-build x86
build-x86

00:28:34

passed #7164
docker-alpine ci-build x86_64
build-x86_64

00:04:41