Enable clang-format-10

Move away from hardcoding the version of clang-format.

Took from:
https://github.com/openbmc/libmctp/blob/f5afcd7e6597dcdeaa475aa7194ecfae2e82d114/format-code.sh#L3

Change-Id: I574d6ea2f1221001754aef36aa8627d270dff178
Signed-off-by: Gunnar Mills <gmills@us.ibm.com>
diff --git a/format-code.sh b/format-code.sh
index d298d36..64bf6e9 100755
--- a/format-code.sh
+++ b/format-code.sh
@@ -14,10 +14,12 @@
 
 echo "Formatting code under $DIR/"
 
+: ${CLANG_FORMAT:=clang-format}
+
 # Only validate certain areas of the code base for
 # formatting due to some imported code in webui
 
 if [ -f ".clang-format" ]; then
-    clang-format-8 -i `git ls-files '*.js'`
+    $CLANG_FORMAT -i `git ls-files '*.js'`
     git --no-pager diff --exit-code
 fi