Fix use of GIT_SHALLOW in external components

External component cmake files are specifying GIT_SHALLOW TRUE for
the content fetch options for fetching upstream content. This
option is intended for cases where a remote branch is being
tracked and only the tip needs to be fetched. To maintain
control over the versions of external components used, a
specific tag or hash should be used as the refspec. For this
behaviour, GIT_SHALLOW TRUE cannot be used as fetches will
fail when the upstream repo changes. This change fixes the
problem.

Signed-off-by: Julian Hall <julian.hall@arm.com>
Change-Id: I61cefb295352b0d2c46f6a426577605b6a3cfae6
diff --git a/external/MbedTLS/MbedTLS.cmake b/external/MbedTLS/MbedTLS.cmake
index ec39e83..6cc1fa2 100644
--- a/external/MbedTLS/MbedTLS.cmake
+++ b/external/MbedTLS/MbedTLS.cmake
@@ -65,7 +65,7 @@
 			BINARY_DIR ${MBEDTLS_BINARY_DIR}
 			GIT_REPOSITORY ${MBEDTLS_URL}
 			GIT_TAG ${MBEDTLS_REFSPEC}
-			GIT_SHALLOW TRUE
+			GIT_SHALLOW FALSE
 		)
 
 		# FetchContent_GetProperties exports mbedtls_SOURCE_DIR and mbedtls_BINARY_DIR variables