Use raw strings for regexes to avoid deprecation warnings

Author: camelid

highfive/newpr.py

@@ -34,8 +34,8 @@
 review_with_reviewer = 'r? @%s\n\n(rust-highfive has picked a reviewer for you, use r? to override)'
 review_without_reviewer = '@%s: no appropriate reviewer found, use r? to override'
 
-reviewer_re = re.compile("\\b[rR]\?[:\- ]*@([a-zA-Z0-9\-]+)")
-submodule_re = re.compile(".*\+Subproject\scommit\s.*", re.DOTALL | re.MULTILINE)
+reviewer_re = re.compile(r"\\b[rR]\?[:\- ]*@([a-zA-Z0-9\-]+)")
+submodule_re = re.compile(r".*\+Subproject\scommit\s.*", re.DOTALL | re.MULTILINE)
 
 rustaceans_api_url = "http://www.ncameron.org/rustaceans/user?username={username}"