Upgrade Python syntax with pyupgrade (#11)

see https://github.com/asottile/pyupgrade

src/z3c/coverage/coveragediff.py

@@ -112,7 +112,7 @@ def warn(filename, message):
 
     """
     module = strip(os.path.basename(filename), '.cover')
-    print('%s: %s' % (module, message))
+    print('{}: {}'.format(module, message))
 
 
 def compare_dirs(olddir, newdir, include=(), exclude=(), warn=warn):
@@ -240,7 +240,7 @@ def __init__(self, web_url=None):
     def warn(self, filename, message):
         """Warn about test coverage regression."""
         module = strip(os.path.basename(filename), '.cover')
-        print('%s: %s' % (module, message))
+        print('{}: {}'.format(module, message))
         if self.web_url:
             url = urljoin(self.web_url, module + '.html')
             print('See ' + url)
@@ -264,7 +264,7 @@ def __init__(self, from_addr, to_addr, subject, web_url=None,
     def warn(self, filename, message):
         """Warn about test coverage regression."""
         module = strip(os.path.basename(filename), '.cover')
-        self.warnings.append('%s: %s' % (module, message))
+        self.warnings.append('{}: {}'.format(module, message))
         if self.web_url:
             url = urljoin(self.web_url, module + '.html')
             self.warnings.append('See ' + url + '\n')

src/z3c/coverage/coveragereport.py

@@ -557,7 +557,7 @@ def make_coverage_reports(path, report_path, opts):
         print(tree)
     rev = get_svn_revision(os.path.join(path, os.path.pardir))
     timestamp = str(datetime.datetime.utcnow()) + "Z"
-    footer = "Generated for revision %s on %s" % (rev, timestamp)
+    footer = "Generated for revision {} on {}".format(rev, timestamp)
     create_report_path(report_path)
     generate_htmls_from_tree(tree, path, report_path, footer)
     generate_overall_html_from_tree(