Bump version suffix to rc2

Cherry-picked
https://github.com/rabbitholecomputing/ZuluSCSI-firmware/commit/a466620ae6754b5d7508ab96ca296fbb7d820a27
so bumping version suffix

src/ZuluSCSI_config.h

@@ -5,7 +5,7 @@
 
 // Use variables for version number
 #define FW_VER_NUM      "1.0.6"
-#define FW_VER_SUFFIX   "rc1"
+#define FW_VER_SUFFIX   "rc2"
 #define ZULU_FW_VERSION FW_VER_NUM "-" FW_VER_SUFFIX
 
 // Configuration and log file paths