Updated mediawiki/extensions
Project: mediawiki/extensions/MobileFrontend  68025f017a0365f5646557835c6cf1c494e1c22b

Make thumbnail caption color darker

Change from #777 to #555. Also make @grayMediumDark #555 instead of
 #565656.

Bug: 67005
Change-Id: I2ed0a1f5f8276c004c830dac6b08b285923feac6