Add a const to satisfy cppcheck

Author: martinhsv

src/utils/base64.cc

@@ -119,7 +119,7 @@ void Base64::decode_forgiven_engine(unsigned char *plain_text,
     int i = 0, j = 0, k = 0;
     int ch = 0;
     static const char b64_pad = '=';
-    static int b64_reverse_t[256] = {
+    static const int b64_reverse_t[256] = {
         -2, -2, -2, -2, -2, -2, -2, -2, -2, -1, -1, -2, -2, -1, -2, -2,
         -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2,
         -1, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, 62, -2, -2, -2, 63,

test/cppcheck_suppressions.txt

@@ -56,7 +56,6 @@ knownConditionTrueFalse:src/operators/validate_url_encoding.cc:77
 knownConditionTrueFalse:src/operators/verify_svnr.cc:87
 rethrowNoCurrentException:headers/modsecurity/transaction.h:306
 rethrowNoCurrentException:src/rule_with_actions.cc:123
-constVariable:src/utils/base64.cc:122
 
 noExplicitConstructor:seclang-parser.hh
 constParameter:seclang-parser.hh