treewide get rid of go 1.12 (#83253)

* treewide Drop unneeded go 1.12 overrides

* Fix packr to be go module compatible.

I updated to version 2.8.0 which is the latest on master.
Then due to the 2 different sets of go modules which are used, I split
the build into two different derivations, then merged them togethor
using symlinkJoin to have the same output structure as the existing derivation.

* Remove consul dependency on go1.12

I updated the consul version to 1.7.2 and flipped it to building using
modules.

* Remove go1.12 from perkeep.

Update the version to the latest unstable on master.

* Update scaleway-cli to not be pinned to go1.12

Switched the version to 1.20

* Update prometheus-varnish-exporter to not depend on go1.12

* Update lnd to build with go1.12

Updated the version
Forced only building subpackages with main to prevent panics over
multiple modules in one repo

* Remove go1.12 from openshift

Had to update the version to 4.1.0 and do a bit of munging to get this
to work

* Remove go1.12 completely.

These are no longer needed.

* Update bazel-watcher and make it build with go 1.14

pkgs/applications/misc/perkeep/default.nix

@@ -13,13 +13,13 @@ let
 
 in buildGoPackage rec {
   name = "perkeep-${version}";
-  version = "unstable-2019-07-29";
+  version = "unstable-2020-03-23";
 
   src = fetchFromGitHub {
     owner = "perkeep";
     repo = "perkeep";
-    rev = "c9f78d02adf9740f3b8d403a1418554293cc9f41";
-    sha256 = "11rin94pjzg0kvizrq9ss42fjw7wfwx3g1pk8zdlhyfkiwwh2rmg";
+    rev = "c2e31370ddefd86b6112a5d891100ea3382a4254";
+    sha256 = "0jf02k20ms7h60wglcq6dj3vqi9rlfww7db5iplgwznbij70c1i4";
   };
 
   goPackagePath = "perkeep.org";