fmt: pickup fix of link failure with clang

fmtlib v7.1.3 contains the fix of https://github.com/fmtlib/fmt/issues/1753

so let's bump up the submodule to the latest master HEAD of fmtlib
for more fixes.

Signed-off-by: Kefu Chai <kchai@redhat.com>

diff --git a/src/fmt b/src/fmt
index 51bf9cfacb644659e5d9c7e6fe66396726f2f4f4..427b53405442872decb69d9735db0fa64106ebe2 160000 (submodule)
--- a/src/fmt
+++ b/src/fmt
@@ -1 +1 @@
-Subproject commit 51bf9cfacb644659e5d9c7e6fe66396726f2f4f4
+Subproject commit 427b53405442872decb69d9735db0fa64106ebe2