fix(tvl-buildkite): Add more missing programs to agent path

... this option really is a pitfall! The list of programs is now the
same as in the upstream module, plus curl and jq.

Change-Id: I29edae4b2400a2724f62df9efa1dc184a8b0af5f

ops/modules/tvl-buildkite.nix

@@ -41,6 +41,8 @@ in {
           coreutils
           curl
           git
+          gnutar
+          gzip
           jq
           nix
         ];