[C/C++] Const qualify version comparison method.

Author: denizevrenci

sbe-tool/src/main/java/uk/co/real_logic/sbe/generation/c/CGenerator.java

@@ -512,7 +512,7 @@ private static CharSequence generateGroupPropertyFunctions(
  " return %3$d;\n" +
  "}\n\n" +
 
- "SBE_ONE_DEF bool %2$s_in_acting_version(struct %1$s *const codec)\n" +
+ "SBE_ONE_DEF bool %2$s_in_acting_version(const struct %1$s *const codec)\n" +
  "{\n" +
  "#if defined(__clang__)\n" +
  "#pragma clang diagnostic push\n" +

sbe-tool/src/main/java/uk/co/real_logic/sbe/generation/cpp/CppGenerator.java

@@ -390,7 +390,7 @@ private static CharSequence generateGroupProperty(
  indent + " return %2$d;\n" +
  indent + " }\n\n" +
 
- indent + " bool %1$sInActingVersion() SBE_NOEXCEPT\n" +
+ indent + " bool %1$sInActingVersion() const SBE_NOEXCEPT\n" +
  indent + " {\n" +
  indent + "#if defined(__clang__)\n" +
  indent + "#pragma clang diagnostic push\n" +