gnu: Add python-google-cloud-core.

* gnu/packages/python-web.scm (python-google-cloud-core): New variable.

gnu/packages/python-web.scm

@@ -97,6 +97,7 @@ (define-module (gnu packages python-web)
   #:use-module (gnu packages python-science)
   #:use-module (gnu packages python-xyz)
   #:use-module (gnu packages qt)
+  #:use-module (gnu packages rpc)
   #:use-module (gnu packages serialization)
   #:use-module (gnu packages sphinx)
   #:use-module (gnu packages texinfo)
@@ -6892,6 +6893,33 @@ (define-public python-google-api-core
 clients.")
     (license license:asl2.0)))
 
+(define-public python-google-cloud-core
+  (package
+    (name "python-google-cloud-core")
+    (version "2.3.0")
+    (source
+     (origin
+       (method url-fetch)
+       (uri (pypi-uri "google-cloud-core" version))
+       (sha256
+        (base32 "0sa66kidgr32dfq9ngha9l362xnqvnqqmssn5my1gd3lc6g65apx"))))
+    (build-system python-build-system)
+    (arguments
+     `(#:phases
+       (modify-phases %standard-phases
+         (replace 'check
+           (lambda* (#:key tests? #:allow-other-keys)
+             (when tests?
+               (invoke "pytest")))))))
+    (propagated-inputs (list python-google-api-core python-google-auth))
+    (native-inputs
+     (list python-grpcio python-pytest))
+    (home-page "https://github.com/googleapis/python-cloud-core")
+    (synopsis "Google Cloud API client core library")
+    (description "This library defines common helpers (e.g. base @code{Client}
+classes) used by all of the @code{google-cloud-*} packages.")
+    (license license:asl2.0)))
+
 (define-public python-w3lib
   (package
     (name "python-w3lib")