Update SBT and SBT plugin versions

[travisbrown]

I just noticed while working on #1253 that some of these versions are out-of-date. I ran the benchmarks locally to confirm that the sbt-jmh update doesn't break anything.

[kailuowang]

Looks like build is going to fail. but #1256 should fix build. Otherwise changes look good to me. 👍

[travisbrown]

@kailuowang Great, thanks—I'll rebase after that's merged. (For the record sbt validate passes locally if I bump the memory in .jvmopts.)

[kailuowang]

@travisbrown thanks for the hint. I tried the same approach in this PR #1257 but it failed pretty miserably (maybe travis just doesn't have that much memory? )

[mikejcurry]

@kailuowang -I understood Travis limitation in terms of memory to be 3G. From Travis FAQ, though don't know how up to date that is.

What hardware are my tests running on?
We use dedicated hardware to ensure full speed for your tests. You have 3GB of memory and up to 2 cores available. Your tests are running directly off SSDs with the most common databases optimized to run off RAM disks.

[codecov-io]

Current coverage is 90.13% (diff: 100%)

Merging #1258 into master will not change coverage

@@             master      #1258   diff @@
==========================================
  Files           243        243          
  Lines          3285       3285          
  Methods        3231       3231          
  Messages          0          0          
  Branches         51         51          
==========================================
  Hits           2961       2961          
  Misses          324        324          
  Partials          0          0          

Powered by Codecov. Last update d8e2671...67eacc7

[travisbrown]

Just rebased this to try out #1256 with the updates.

[johnynek]

👍

[fthomas]

👍