Release 0.7.1 (google#327)

Release 0.7.0 (google#312)

Release 0.6.1 (google#306)

Release 0.6.0 (google#288)

Release 0.5.0 (google#269)

Release 0.4.3 (google#235)

Release 0.4.2 (google#228)

Release 0.4.1 (google#204)

Release 0.4.0 (google#190)

Support Node 14 on Windows and release 0.3.1 (google#162)

I didn't test Node 14 on Windows in google#160, so I missed two issues:

- We use `replaceAll`, but only on Windows. Fixed by using `replace` instead, and by dropping `lib` down to `es2020` in `tsconfig.json` (which catches this error in `tsc`).

- There is a subtle difference between how environment variables are treated when `spawn`ing between Node 14 and 16 on Windows, relating to the way environment variables are case-insensitive on Windows. Full details in `test/windows.ts`.

I've also expanded to the test matrix to just test all OS/Node permutations that we support, because obviously it is not safe to assume anything (especially on Windows, but let's be safe and not assume anything about macOS acting exactly like Linux either).

Actually fixes google#160