go: Initial commit

Common packages for working on Go projects.

I frequently use this from my editor with:

- https://github.com/flox/flox-direnv

And the following in `.envrc`:

    use flox --remote floxenvs/go

In future the editor dependencies could be broken out to a separate
`go-editor` or `go-lsp` environment.

The `GOENV` hook is copied from our `init --auto-setup` hook with the
exception of:

1. Path is modified from `goenv` to `go` to match the other example
   environments in this repo
2. `go get .` is omitted because it's surprising to fetch dependencies
   when activating an environment and we have plans to remove it from
   the default manifest.

The example module which includes a third-party module to prove that
dependency fetching still works is taken from:

- https://go.dev/blog/using-go-modules

The minimum Go version is currently pinned, both in the `manifest.toml`
and `go.mod`, at the latest stable major and minor version. It should
continue to work after a `flox upgrade` assuming that there are no
breaking changes.

.gitignore

@@ -4,3 +4,4 @@
 /*/.flox/cache
 /*/.flox/log
 /*/.flox/run
+go/hello

README.md

@@ -6,6 +6,7 @@
 | :--- | :-----: | :----: | :-----: | :---------- |
 | |
 | **Languages:** |
+| `go`  | ✅ | ✅ | ✅ | |
 | `python-poetry`  | ✅ | ✅ | ✅ | Python environment using poerty |
 | `ruby`  | ✅ | ✅ | ✅ | Ruby environment |
 | `rust`  | ✅ | ✅ | ✅ | Rust environment |

go/.flox/.gitignore

@@ -0,0 +1,4 @@
+run/
+cache/
+lib/
+log/

go/.flox/env.json

@@ -0,0 +1,4 @@
+{
+  "name": "go",
+  "version": 1
+}