Add nginx 1.17.3, remove nginx 1.17.2
Add nginx 1.17.3, remove nginx 1.17.2

for stack(s) cflinuxfs2, cflinuxfs3 [#167876323]

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