Bump flatcc version (#6853)

Resolve fallthrough warning in RISC-V cross-compilation.
https://github.com/dvidelabs/flatcc/pull/203
diff --git a/SUBMODULE_VERSIONS.txt b/SUBMODULE_VERSIONS.txt
index dae5bc0..fff5393 100644
--- a/SUBMODULE_VERSIONS.txt
+++ b/SUBMODULE_VERSIONS.txt
@@ -1,6 +1,6 @@
 39c8d58a76ce7c3398786ee96a452668e8392af7 third_party/benchmark
 5916273f79a21551890fd3d56fc5375a78d1598d third_party/cpuinfo
-32aabef14ccc0e3ac15602c99476d25dcd230d19 third_party/flatcc
+62a7f88611af08c68be5485ce6d9c7e92474eab8 third_party/flatcc
 aa533abfd4232b01f9e57041d70114d5a77e6de0 third_party/googletest
 88b845dee001723c4a0db1fe5477de735b6d3bb0 third_party/liburing
 acd6f6f014c25e46363e718381e0b35205df2d83 third_party/libyaml
diff --git a/third_party/flatcc b/third_party/flatcc
index 32aabef..62a7f88 160000
--- a/third_party/flatcc
+++ b/third_party/flatcc
@@ -1 +1 @@
-Subproject commit 32aabef14ccc0e3ac15602c99476d25dcd230d19
+Subproject commit 62a7f88611af08c68be5485ce6d9c7e92474eab8