add changelog notes for Flex, Bison dependency bump

A series of commits beginning with 8c099fc032074a0bb5961d67ef4df05ddca7eba4
raised the minimum required versions of Flex and Bison. No changelog entries
were added at the time because we were working under an ad hoc policy that
changes that only affected users compiling from source were not eligible for
changelog entries. This has since changed. Related to #1806.

diff --git a/CHANGELOG.md b/CHANGELOG.md
index d1272e851e7783f09bd2acc4f28e617fa644dab6..e10d397ea2859ee3515a6463b80b1bc894cff32b 100644 (file)
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -17,6 +17,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Build system work arounds for GCC 3 have been removed
 - Incomplete support for running the test suite under CMake has been removed
 - Portable source tarballs now use the “ustar” POSIX format
+- Minimum version of Flex required to build Graphviz is now 2.5.2
+- Minimum version of Bison required to build Graphviz is now 3.0
 
 ### Fixed
 - gvpr: line numbers in gvpr errors/warnings are incorrect #1594