Add R-project mirror domain for build pattern detection

We use ftp.osuosl.org/pub/cran/ as a CRAN mirror, and autospec uses the
URL to select the R build pattern, so make sure that URL is also
included.

autospec/config.py

@@ -347,7 +347,7 @@ def set_build_pattern(self, pattern, strength):
     def detect_build_from_url(self, url):
         """Detect build patterns and build requirements from the patterns detected in the url."""
         # R package
-        if "cran.r-project.org" in url or "cran.rstudio.com" in url:
+        if "cran.r-project.org" in url or "cran.rstudio.com" in url or "/pub/cran/" in url:
             self.set_build_pattern("R", 10)
 
         # python