Tag language-0.26.0 release

Cut release of vision API. (googleapis#3677)

Also bumping the version on the uber-package.

Speech GAPIC to master (googleapis#3607)

* Vendor the GAPIC for Speech.

* Speech Partial Veneer (googleapis#3483)

* Update to docs based on @dhermes catch.

* Fix incorrect variable.

* Fix the docs.

* Style fixes to unit tests.

* More PR review from me.

Making requirements tighter for "stable" packages in 0.26.1 release. (g…

…oogleapis#3586)

Making requirements tighter for "stable" packages in 0.25.1 release. (g…

…oogleapis#3584)

Making requirements tighter for "stable" packages in error reporting …

…0.25.1 release. (googleapis#3588)

Making requirements tighter for "stable" packages in error reporting …

…0.24.3 release. (googleapis#3587)

Tag umbrella 0.26.0 release.

Tag vision-0.25.0 release.

Tag translate-0.25.0 release.