Fix include guards in regex and utime

The include_guard in both regex and utime was "_TEMPLATE_H", this meant that including both wasn't possible.
Their header guards should be consistent with the header files as well.
Changed _TEMPLATE_H to _REGEX_H and _UTIME_H in /regex/cbindgen.toml and /utime/cbindgen.toml respectively.

src/header/regex/cbindgen.toml

@@ -1,5 +1,5 @@
 sys_includes = ["sys/types.h"]
-include_guard = "_TEMPLATE_H"
+include_guard = "_REGEX_H"
 language = "C"
 style = "Type"
 

src/header/utime/cbindgen.toml

@@ -1,5 +1,5 @@
 sys_includes = []
-include_guard = "_TEMPLATE_H"
+include_guard = "_UTIME_H"
 language = "C"
 style = "Tag"