Update README.md for 1.0-RC4
Update README.md for 1.0-RC4

Signed-off-by: Tyler Battle <ae42760ef71e07cdc78c21849b44551816bda917@battle.ca>

mtCarto/geogig,jdgarrett/geogig,jdgarrett/geogig,jdgarrett/geogig,mtCarto/geogig,mtCarto/geogig