hugo: add git as a dependency

Hugo needs Git to find meta informations such as the pubDate

images/hugo/default.nix

@@ -1,6 +1,8 @@
 { buildCLIImage
 , hugo
+, gitReallyMinimal
 }:
 buildCLIImage {
   drv = hugo;
+  extraContents = [ gitReallyMinimal ];
 }

lib/buildCLIImage.nix

@@ -5,6 +5,7 @@
 { drv # derivation to build the image for
   # Name of the binary to run by default
 , binName ? (builtins.parseDrvName drv.name).name
+, extraContents ? []
 , meta ? drv.meta
 }:
 let
@@ -17,7 +18,7 @@ let
       # most program need TLS certs
       cacert
       drv
-    ];
+    ] ++ extraContents;
 
     config = {
       Cmd = [ "/bin/${binName}" ];