community/ausweisapp2: upgrade to 1.26.7

https://github.com/Governikus/AusweisApp2/releases/tag/1.26.7

current version fails build on 3.19 builders

• http://build.alpinelinux.org/buildlogs/build-3-19-aarch64/community/ausweisapp2/ausweisapp2-1.26.6-r0.log
• http://build.alpinelinux.org/buildlogs/build-3-19-s390x/community/ausweisapp2/ausweisapp2-1.26.6-r0.log
• http://build.alpinelinux.org/buildlogs/build-3-19-armv7/community/ausweisapp2/ausweisapp2-1.26.6-r0.log