update composer to 1.7.2, drop 1.4 branch

library/composer

@@ -3,9 +3,9 @@
 Maintainers: Composer (@composer), Rob Bast (@alcohol)
 GitRepo: https://github.com/composer/docker.git
 
-Tags: 1.7.1, 1.7, 1, latest
+Tags: 1.7.2, 1.7, 1, latest
 Architectures: amd64, arm32v6, arm64v8, i386, ppc64le
-GitCommit: 1a90a09f7ca31795e8ae264336747ed59f5e4e69
+GitCommit: edf4f0abf50da5d967408849434b9053a195b65f
 Directory: 1.7
 
 Tags: 1.6.5, 1.6
@@ -17,8 +17,3 @@ Tags: 1.5.6, 1.5
 Architectures: amd64, arm32v6, arm64v8, i386, ppc64le
 GitCommit: 615ac2f7541ce6fc9538e513326e3aa6a2bff749
 Directory: 1.5
-
-Tags: 1.4.3, 1.4
-Architectures: amd64, arm32v6, arm64v8, i386, ppc64le
-GitCommit: 615ac2f7541ce6fc9538e513326e3aa6a2bff749
-Directory: 1.4