[releng] convert-to-tarballs: avoid yaml safety warning

[Michael Catanzaro <mcatanzaro src gnome org>]

commit bdf5f180dd9faa55e741e6983329125cae924c8b
Author: Michael Catanzaro <mcatanzaro gnome org>
Date:   Mon Feb 17 16:30:19 2020 -0600

    convert-to-tarballs: avoid yaml safety warning
    
    Apparently if we use the word "safe" that makes things safer. What is
    this really changing? I have no idea, but it silences a longstanding
    warning.

 tools/smoketesting/convert-to-tarballs.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/tools/smoketesting/convert-to-tarballs.py b/tools/smoketesting/convert-to-tarballs.py
index 0853932..d14cdf1 100755
--- a/tools/smoketesting/convert-to-tarballs.py
+++ b/tools/smoketesting/convert-to-tarballs.py
@@ -642,7 +642,7 @@ class ConvertToTarballs:
         self.ignored_tarballs = []
 
         with open(os.path.join(directory, 'project.conf')) as f:
-            projectconf = yaml.load(f)
+            projectconf = yaml.safe_load(f)
             self.aliases = projectconf['aliases']
 
     def find_tarball_by_name(self, name):