Increment devel to 1.19.5, which 1.18.x will accept as an upgrade option.
Merge pull request #181 from sinzui/inc-1.19.5

Increment devel to 1.19.5

We cannot switch to 1.21-alpha1 until 1.20.0 is release. 1.18.x panics when it sees alphas in upgrade candidates. 1.18.x will accept 1.19.5 as an upgrade option in tests.