Update CHANGELOG.md

Author: haampie

CHANGELOG.md

@@ -1,5 +1,12 @@
 # Changelog
 
+## v2.1.1
+
+- For Spack `v0.22.0.dev0` and higher `spack install` without further flags can
+  install prebuilt binaries from the build cache without erroring about missing
+  signatures on the binaries. The default build cache is marked as "unsigned".
+- Disable `/etc/spack` and `~/.spack` config files, only use `$spack/etc`
+
 ## v2.1.0
 
 - Support shell aware commands like `spack env activate` and `spack load` in the `spack-bash`
@@ -10,4 +17,4 @@
 - Enable build cache from https://github.com/spack/github-actions-buildcache
 - Enable color output by default
 - Remove custom bootstrapped binaries for clingo
-- Remove option for choosing the concretizer
+- Remove option for choosing the concretizer