docs(readme): bump to 0.75.0 + document v0.73-v0.75 PXF API additions - #40

Encountered a fatal error while running "/opt/hostedtoolcache/CodeQL/2.25.4/x64/codeql/codeql database finalize --finalize-dataset --threads=4 --ram=14575 /home/runner/work/_temp/codeql_databases/java". Exit code was 32 and last log line was: CodeQL could not process any code written in Java/Kotlin. For more information, review our troubleshooting guide at https://gh.io/troubleshooting-code-scanning/no-source-code-seen-during-build . See the logs for more details.