Add IndentCaseBlocks to .clang-format

This option is supported since clang-format version 11. Just use the
default value for now, to not change the formatting but ensure we have
a compatible version of the tool available where required.

Bug: b/144825072
Change-Id: If5787f7a8f3502bae5c16e561599f87f4b90f6d6
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/50528
Presubmit-Ready: Nicolas Capens <nicolascapens@google.com>
Kokoro-Result: kokoro <noreply+kokoro@google.com>
Tested-by: Nicolas Capens <nicolascapens@google.com>
Reviewed-by: Alexis Hétu <sugoi@google.com>

.clang-format

diff --git a/.clang-format b/.clang-format
index 9529a46..d5c422b 100644
--- a/.clang-format
+++ b/.clang-format
@@ -71,6 +71,7 @@
   - Regex:           '.*'
     Priority:        5
 IncludeIsMainRegex: '([-_](test|unittest))?$'
+IndentCaseBlocks: false
 IndentCaseLabels: true
 IndentPPDirectives: AfterHash
 IndentWidth:     4