gnu: Add go-github-com-emersion-go-mbox.

* gnu/packages/golang.scm (go-github-com-emersion-go-mbox): New
  variable.

Signed-off-by: Raghav Gururajan <rg@raghavgururajan.name>

gnu/packages/golang.scm

@@ -6898,6 +6898,29 @@ filters for Go.")
      "This package provides a Go library for authenticating emails.")
     (license license:expat)))
 
+(define-public go-github-com-emersion-go-mbox
+  (package
+    (name "go-github-com-emersion-go-mbox")
+    (version "1.0.3")
+    (source (origin
+              (method git-fetch)
+              (uri (git-reference
+                    (url "https://github.com/emersion/go-mbox")
+                    (commit (string-append "v" version))))
+              (file-name (git-file-name name version))
+              (sha256
+               (base32
+                "0vnadh2khx7sxn0irrd8gz8ra02x7ij0q8zglq3rqffqil06nliv"))))
+    (build-system go-build-system)
+    (arguments
+     (list #:import-path "github.com/emersion/go-mbox"))
+    (home-page "https://github.com/emersion/go-mbox")
+    (synopsis "Go library for handling @code{mbox} files")
+    (description
+     "This package provides a library for parsing and formatting
+@code{mbox} files.")
+    (license license:expat)))
+
 (define-public go-github-com-fatih-color
   (package
     (name "go-github-com-fatih-color")