Bump to 0.1.17.2

docs/CHANGELOG.md

 # Revision history for ghcup
 
+## 0.1.17.2 -- 2021-09-30
+
+* Honour GHC bootstrap compiler during git clone stages wrt [#250](https://gitlab.haskell.org/haskell/ghcup-hs/-/issues/250)
+* Speed up `unset` command
+* Fix `--overwrite-version` for `ghcup compile ghc` wrt [#253](https://gitlab.haskell.org/haskell/ghcup-hs/-/issues/253)
+* Apply patches before bootstrap
+
 ## 0.1.17.1 -- 2021-09-26
 
 * Fix `NO_COLOR`

ghcup.cabal

 cabal-version:      3.0
 name:               ghcup
-version:            0.1.17.1
+version:            0.1.17.2
 license:            LGPL-3.0-only
 license-file:       LICENSE
 copyright:          Julian Ospald 2020