Documentation fix: Add -lbz2 link flag

[Aurélien DEROIDE]

On ubuntu22, I had to add -lbz2 to the CGO_LDFLAGS to successfully run go build

I'd suggest to add it in the Readme build flags:

CGO_CFLAGS="-I/path/to/rocksdb/include" \
CGO_LDFLAGS="-L/path/to/rocksdb -lrocksdb -lstdc++ -lm -lz -lsnappy -llz4 -lzstd -lbz2" \
  go build

Thanks fro your work

[Linh Tran Tuan]

Thank you for suggestion. I think it's reasonable to update the README.

To clarify why bz2 is needed by your case:

• your rocksdb was built with bz2 support
• it's root cause why you need to specify bz2 link

[Linh Tran Tuan]

I updated README. Thank you.