url2purl: linter -> reformat cran functions

Author: schischi

src/packageurl/contrib/purl2url.py

@@ -185,6 +185,7 @@ def build_rubygems_repo_url(purl):
     elif name:
         return f"https://rubygems.org/gems/{name}"
 
+
 @repo_router.route("pkg:cran/.*")
 def build_cran_repo_url(purl):
     """

src/packageurl/contrib/url2purl.py

@@ -284,9 +284,7 @@ def build_rubygems_purl(uri):
     "https?://packagemanager.rstudio.com/cran/.*",
 )
 def build_cran_purl(uri):
-    cran_pattern = (
-        r"^https?://(cran\.r-project\.org|packagemanager\.rstudio\.com/cran)/.*?src/contrib/(?P<name>.+)_(?P<version>.+)\.tar.gz$"
-    )
+    cran_pattern = r"^https?://(cran\.r-project\.org|packagemanager\.rstudio\.com/cran)/.*?src/contrib/(?P<name>.+)_(?P<version>.+)\.tar.gz$"
     qualifiers = {}
     if "//cran.r-project.org/" not in uri:
         qualifiers["download_url"] = uri