Updated nginx.

- mainline nginx is bumped to 1.13.9
- alpine mainline builds are now using alpine 3.7.

library/nginx

@@ -1,24 +1,26 @@
-# this file is generated via https://github.com/nginxinc/docker-nginx/blob/12fbe201aef2ffebba809e223460f5bf3dc9b445/generate-stackbrew-library.sh
+# this file is generated via https://github.com/nginxinc/docker-nginx/blob/80d4df4c9dac780f8906c96928fac484c6559b20/generate-stackbrew-library.sh
 
 Maintainers: NGINX Docker Maintainers <[email protected]> (@nginxinc)
 GitRepo: https://github.com/nginxinc/docker-nginx.git
 
-Tags: 1.13.8, mainline, 1, 1.13, latest
+Tags: 1.13.9, mainline, 1, 1.13, latest
 Architectures: amd64, arm32v7, arm64v8, i386, ppc64le, s390x
-GitCommit: f8fad321cf58d5cbcafa3d9fa15314b8a77b5e65
+GitCommit: dbd053d52727bc8db0fec704caa22b8e0d5f6c84
 Directory: mainline/stretch
 
-Tags: 1.13.8-perl, mainline-perl, 1-perl, 1.13-perl, perl
+Tags: 1.13.9-perl, mainline-perl, 1-perl, 1.13-perl, perl
 Architectures: amd64, arm32v7, arm64v8, i386, ppc64le, s390x
-GitCommit: f8fad321cf58d5cbcafa3d9fa15314b8a77b5e65
+GitCommit: dbd053d52727bc8db0fec704caa22b8e0d5f6c84
 Directory: mainline/stretch-perl
 
-Tags: 1.13.8-alpine, mainline-alpine, 1-alpine, 1.13-alpine, alpine
-GitCommit: f8fad321cf58d5cbcafa3d9fa15314b8a77b5e65
+Tags: 1.13.9-alpine, mainline-alpine, 1-alpine, 1.13-alpine, alpine
+Architectures: amd64, arm32v6, arm64v8, i386, ppc64le, s390x
+GitCommit: dbd053d52727bc8db0fec704caa22b8e0d5f6c84
 Directory: mainline/alpine
 
-Tags: 1.13.8-alpine-perl, mainline-alpine-perl, 1-alpine-perl, 1.13-alpine-perl, alpine-perl
-GitCommit: f8fad321cf58d5cbcafa3d9fa15314b8a77b5e65
+Tags: 1.13.9-alpine-perl, mainline-alpine-perl, 1-alpine-perl, 1.13-alpine-perl, alpine-perl
+Architectures: amd64, arm32v6, arm64v8, i386, ppc64le, s390x
+GitCommit: dbd053d52727bc8db0fec704caa22b8e0d5f6c84
 Directory: mainline/alpine-perl
 
 Tags: 1.12.2, stable, 1.12