Add project.yaml for libxslt (#574)

I added dominicc@chromium.org and ddkilzer@apple.com to auto_ccs.
They're already listed in libxml2's project.yaml and I worked with both
of them when reporting libxslt issues in the past.

projects/libxslt/project.yaml

@@ -0,0 +1,9 @@
+homepage: "http://www.xmlsoft.org/libxslt/"
+primary_contact: "wellnhofer@aevum.de"
+auto_ccs:
+  - "dominicc@chromium.org"
+  - "ddkilzer@apple.com"
+sanitizers:
+  - address
+  - memory
+  - undefined