gnu: python-language-server: Update to 0.29.1.

* gnu/packages/python-xyz.scm (python-language-server): Update to 0.29.1.
[inputs]: Add python-flake8

gnu/packages/python-xyz.scm

@@ -3121,23 +3121,17 @@ (define-public python-pydocstyle
 Server (PLS).")
     (license license:expat)))
 
-;; XXX: We must use a non-release version since the latest release version
-;; requires python-jedi version < 0.15.
 (define-public python-language-server
-  (let ((commit "c3cab77a85b1de4af1aec1bafea6a7320d6baec5")
-        (revision "1"))
   (package
     (name "python-language-server")
-      (version (git-version "0.28.3" revision commit))
+    (version "0.29.1")
     (source
      (origin
-         (method git-fetch)
-         (uri (git-reference
-               (url "https://github.com/palantir/python-language-server.git")
-               (commit commit)))
+       (method url-fetch)
+       (uri (pypi-uri "python-language-server" version))
        (sha256
         (base32
-           "1q0xdwgln09sh58j0ryygj92hfgdhwcs57zjvqihya23jr5v0bz4"))))
+         "1f8qlflh6j3s7qfmzhirpl8fgidl6f0qbakdmiml96wdxzvka0s3"))))
     (build-system python-build-system)
     (propagated-inputs
      `(("python-pluggy" ,python-pluggy)
@@ -3150,6 +3144,7 @@ (define-public python-language-server
        ("python-mccabe" ,python-mccabe)
        ("python-rope" ,python-rope)
        ("python-autopep8" ,python-autopep8)
+       ("python-flake8" ,python-flake8)
        ("python-pylint" ,python-pylint)))
     (home-page "https://github.com/palantir/python-language-server")
     (synopsis "Python implementation of the Language Server Protocol")
@@ -3158,7 +3153,7 @@ (define-public python-language-server
 language specification for the Language Server Protocol (LSP).  This tool is
 used in text editing environments to provide a complete and integrated
 feature-set for programming Python effectively.")
-      (license license:expat))))
+    (license license:expat)))
 
 (define-public python-black
   (package