Bump versionCode.
Bump versionCode.

This bumps the versionCode to 26*, to reflect the advancement to our
current K-release.

Change-Id: I80c6205a58cd20d55674bffdc829d34c17c556e3

dbrant/apps-android-wikipedia,wikimedia/apps-android-wikipedia,dbrant/apps-android-wikipedia,wikimedia/apps-android-wikipedia,wikimedia/apps-android-wikipedia,dbrant/apps-android-wikipedia,dbrant/apps-android-wikipedia,dbrant/apps-android-wikipedia,wikimedia/apps-android-wikipedia