Update CHANGELOG

Author: William McLendon

CHANGELOG.md

@@ -20,6 +20,19 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ## [0.3.1] <!-- YYYY-MM-DD --> [Unreleased]
 #### Added
 #### Changed
+- Changes to `opt-set-cmake-var` behaviour:
+  - Trigger a WARNING if `PARENT_SCOPE` and a _TYPE_ is provided since CMake
+    requires TYPED vars to be CACHE vars and `PARENT_SCOPE` will force the
+    var to be considered a non CACHE var that would store the parameters
+    before `PARENT_SCOPE` in the call as _list_ entries.
+  - Trigger an exception if `PARENT_SCOPE` and `FORCE` are both provided since
+    `FORCE` is only valid for CACHE variables but `PARENT_SCOPE` is only valid
+    for non-CACHE vars (and as noted above will _force_ the `set()` operation
+    to be a non-CACHE var which then triggers a CMake error because `FORCE` is
+    invalid to that form of `set()`.
+  - **bash** generated options that have a TYPE and `PARENT_SCOPE` are processed
+    to generate the same _list_ string that would be generated by the matching
+    `set()` operation (with the warning).
 - Revert(ish) the modifications from MR12 which removed the error when generating
   BASH output if there is an unhandled CMake variable left hanging around.
   Rather than make this an unavoidable error though, ExpandVarsInText now inherits