Docker: use the correct image tag
We changed this from `ubuntu20` to `ubuntu-20.04` and there was a missing change
here.
@@ -527,7 +527,7 @@ class CommunityBaseSettings(Settings):
RTD_DOCKER_BUILD_SETTINGS = {
# Mapping of build.os options to docker image.
'os': {
- 'ubuntu-20.04': f'{DOCKER_DEFAULT_IMAGE}:ubuntu20',
+ 'ubuntu-20.04': f'{DOCKER_DEFAULT_IMAGE}:ubuntu-20.04',
},
# Mapping of build.tools options to specific versions.
'tools': {
