Update changelog for v0.2.0

Author: tarleb

CHANGELOG.md

@@ -1,5 +1,34 @@
 # Revision history for hslua-module-system
 
+## 0.2.0 -- 2019-05-01
+
+All fields and functions are now exported from the Haskell module under
+the same name as that used in Lua.
+
+### New fields
+
+- `arch`: processor architecture.
+- `compiler_name`: Haskell compiler that was used to compile the module.
+- `compiler_version`: version of the compiler.
+- `os`: operating system.
+
+### New functions
+
+- `mkdir`: create a new directory.
+- `rmdir`: remove a directory.
+- `with_env`: perform action with custom environment.
+- `with_wd`: perform action in another directory.
+
+### Removed or renamed functions
+
+- `currentdir` was renamed to `getwd`.
+- `chdir` was renamed to `setwd`.
+- `pwd` was removed.
+
+### Misc
+
+- Fix typos and copy-paste errors in docs, tests.
+
 ## 0.1.0 -- 2019-04-26
 
-* First version. Released on an unsuspecting world.
+- First version. Released on an unsuspecting world.