Update git submodules
- Update extensions/ImageMap from branch 'REL1_39' to 1ec0a60052125ed7b9079757821395e9e9f38eda
- build: Update MediaWiki requirement to 1.39.0
Change-Id: Ib479533da960edac4cee1cddcc9a46764887f0ae
- build: Update MediaWiki requirement to 1.39.0