fix: process label was causing PRs to be closed

[bcoe]

let's just close open issues with autorelease: pending by default, process is used too commonly.

[chingor13]

Should release-please use it's own reserved labels to identify it's open PRs?

[bcoe]

@chingor13 this is how I was picturing autorelease: pending, which seems unlikely for someone to add if it's not an autorelease PR; at some point we just made the logic less restrictive and caught the process labels too.

[codecov]

Codecov Report

Merging #358 into master will decrease coverage by 44.05%.
The diff coverage is 0%.

@@            Coverage Diff             @@
##           master    #358       +/-   ##
==========================================
- Coverage   85.55%   41.5%   -44.06%     
==========================================
  Files          26       3       -23     
  Lines        3054    1118     -1936     
  Branches      264      40      -224     
==========================================
- Hits         2613     464     -2149     
- Misses        430     650      +220     
+ Partials       11       4        -7

Impacted Files	Coverage Δ
src/github.ts	33.81% <0%> (-34.89%)	⬇️
src/util/checkpoint.ts	74.19% <0%> (-16.13%)	⬇️
src/graphql-to-commits.ts	74.17% <0%> (-12.64%)	⬇️
src/updaters/java/pom-xml.ts
src/releasers/php-yoshi.ts
src/updaters/terraform/readme.ts
src/updaters/java/readme.ts
src/util/coerce-option.ts
src/updaters/root-composer.ts
... and 16 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update b096454...6f4de5e. Read the comment docs.