Merge ~sylvain-pineau/checkbox-ng:fix-provider-manager-encoding into checkbox-ng:master

[Sylvain Pineau]

I can't use (yet) subprocess.run encoding, it's 3.6+. Fallback to universal_newlines

[Sylvain Pineau (sylvain-pineau)]

self-approved

review: Approve

diff --git a/plainbox/provider_manager.py b/plainbox/provider_manager.py
index 58748ae..4332eb1 100644
--- a/plainbox/provider_manager.py
+++ b/plainbox/provider_manager.py
@@ -1345,7 +1345,7 @@ def create_inline_shellcheck_test(command):
         result = subprocess.run(
             ['shellcheck', '-', '--shell=bash'],
             input=command,
-            encoding='ascii')
+            universal_newlines=True)
         self.assertEqual(result.returncode, 0)
     return run_inline_shellcheck