Adding librdkafka versions 1.9.2, 2.0.2 (spack#37501)

Co-authored-by: Alec Scott <hi@alecbcs.com>

Set version to 0.19.2

Set version to 0.19.1

ensure view projections for extensions always point to extendee

Make CI work for Windows on a push to the release branch

Add Changelog for v0.17.3, bump version number

update changelog for v0.18.0 (spack#30905)

update ffmpeg to avoid building for non-web environments

update ffmpeg package to auto-detect variants for emscripten

fix zlib and bzip2