d Spell out the Options migration plan

Co-Authored-By: Llewellyn Falco <[email protected]>

Author: claremacrae

build/relnotes_x.y.z.md

@@ -1,6 +1,9 @@
 See the [v.x.y.z milestone](https://github.com/approvals/ApprovalTests.cpp/milestone/8?closed=1) for the full list of changes.
 
 * **Breaking changes**
+    * **Planned deprecation:** The overloads of `verify()`, `verifyAll()` and `verifyAllCombinations()` which take a `Reporter` have been deprecated.
+        * The `Reporter` argument is `replaced` by Options - see below.
+        * By default, there is currently no change, but this release marks the start of the [plan to remove them](/doc/explanations/WhyWeAreConvertingToOptions.md#the-plan).
     * If you happen to have specialised `StringUtils::toString()`, you would now need to specialize `StringMaker::toString()` instead.
         * Note: this was previously unsupported behavior, so we are not bumping the major version number.
         * Here is how to update your code: