gnu: go-github.com-jessevdk-go-flags: Update to 1.5.0.

* gnu/packages/golang.scm (go-github.com-jessevdk-go-flags): Update to 1.5.0.
[arguments]: Add custom phase to fix tests.
[propagated-inputs]: Add go-golang-org-x-sys.

gnu/packages/golang.scm

@@ -2107,7 +2107,7 @@ specified by @uref{https://tools.ietf.org/html/rfc2141, IETF RFC 2141}.")
 (define-public go-github.com-jessevdk-go-flags
   (package
     (name "go-github.com-jessevdk-go-flags")
-    (version "1.3.0")
+    (version "1.5.0")
     (source (origin
               (method git-fetch)
               (uri (git-reference
@@ -2115,11 +2115,19 @@ specified by @uref{https://tools.ietf.org/html/rfc2141, IETF RFC 2141}.")
                     (commit (string-append "v" version))))
               (file-name (git-file-name name version))
               (sha256
-               (base32
-                "1jk2k2l10lwrn1r3nxdvbs0yz656830j4khzirw8p4ahs7c5zz36"))))
+               (base32 "13ixw1yx4bvcj66lkc8zgwf9j7gkvj686g991gycdsafvdvca0lj"))))
     (build-system go-build-system)
     (arguments
-     '(#:import-path "github.com/jessevdk/go-flags"))
+     '(#:import-path "github.com/jessevdk/go-flags"
+       #:phases
+       (modify-phases %standard-phases
+         (add-after 'unpack 'fix-tests
+           (lambda _
+             ;; SOURCE_DATE_EPOCH messes with the date on the man page test.
+             (substitute* "src/github.com/jessevdk/go-flags/help_test.go"
+               (("TestMan") "DisabledTestMan")))))))
+    (propagated-inputs
+     (list go-golang-org-x-sys))
     (synopsis "Go library for parsing command line arguments")
     (description
      "The @code{flags} package provides a command line option parser.  The