revert default version line to 1.19
revert default version line to 1.19

Signed-off-by: Amelia Castilla <54f3f6e07f43db2ab1d225207b300d2c050958d3@vmware.com>
Co-authored-by: Amelia Castilla <54f3f6e07f43db2ab1d225207b300d2c050958d3@vmware.com>

cloudfoundry/staticfile-buildpack,cloudfoundry/staticfile-buildpack,cloudfoundry/staticfile-buildpack,cloudfoundry/staticfile-buildpack