package/docker-credential-gcr: add LICENSE hash

The hash has for the license file been missing since the package was
introduced in commit 992d43b37356 (package/docker-credential-gcr: new
package).

Add it now.

Signed-off-by: Yann E. MORIN <yann.morin@orange.com>
Signed-off-by: Julien Olivain <ju.o@free.fr>

package/docker-credential-gcr/docker-credential-gcr.hash

@@ -1,2 +1,3 @@
 # Locally computed
 sha256  126fdbf7351d2c7aaee6c525d9660738519eae53eeef77920b105fd4d1bc5dbd  docker-credential-gcr-v2.1.26-git4-go2.tar.gz
+sha256  c71d239df91726fc519c6eb72d318ec65820627232b2f796219e87dcf35d0ab4  LICENSE