Bump buildroot to 2019.02

bsp/buildroot/docs/manual/adding-packages.txt

@@ -9,8 +9,9 @@ applications) can be integrated into Buildroot. It also shows how
 existing packages are integrated, which is needed for fixing issues or
 tuning their configuration.
 
-When you add a new package, be sure to test it in various conditions;
-see xref:testing-package[]
+When you add a new package, be sure to test it in various conditions
+(see xref:testing-package[]) and also check it for coding style (see
+xref:check-package[]).
 
 include::adding-packages-directory.txt[]
 
@@ -38,6 +39,8 @@ include::adding-packages-meson.txt[]
 
 include::adding-packages-cargo.txt[]
 
+include::adding-packages-golang.txt[]
+
 include::adding-packages-kernel-module.txt[]
 
 include::adding-packages-asciidoc.txt[]