Make tests pass in 2020

moving this beyond 2038 requires fixes on 32-bit systems to avoid errors:
   File "/home/abuild/rpmbuild/BUILD/python3-saml-1.6.0/src/onelogin/sam
.py", line 419, in parse_SAML_to_time
     data = datetime.strptime(timestr, '%Y-%m-%dT%H:%M:%SZ')
 TypeError: strptime() argument 1 must be string, not long

Author: bmwiedemann

tests/data/metadata/metadata_settings1.xml

@@ -1,6 +1,6 @@
 <?xml version="1.0"?>
 <md:EntityDescriptor xmlns:md="urn:oasis:names:tc:SAML:2.0:metadata"
-                     validUntil="2020-03-05T18:19:11Z"
+                     validUntil="2037-03-05T18:19:11Z"
                      cacheDuration="PT1594475551S"
                      entityID="http://stuff.com/endpoints/metadata.php">
     <md:SPSSODescriptor AuthnRequestsSigned="false" WantAssertionsSigned="false" protocolSupportEnumeration="urn:oasis:names:tc:SAML:2.0:protocol">