No `bootstrap` files in Hackage cabal-install tar ball

**Describe the bug**

[cabal-install-3.4.0.0.tar.gz as distributed on hackage doesn't include bootstrap directory](
http://hackage.haskell.org/package/cabal-install-3.4.0.0/src/).

These files are very useful when bootstrapping cabal-install without having a previous version handy, e.g. in my [OpenBSD port](https://github.com/blackgnezdo/ports/blob/ghc-8.10/devel/cabal/Makefile). I was previously using an rc-tagged bundle on github and hoping to change the dependency to Hackage instead.

**Expected behavior**

Enough files available on Hackage to build all of cabal-install.

**System information**
- OpenBSD
- `cabal-3.4.0.0`, `ghc-8.10.3`