metadata: RequiresRoot is boolean, according to docs

"Set this optional field to ‘True’ if the application requires root
privileges to be usable."
https://f-droid.org/docs/Build_Metadata_Reference/#RequiresRoot

fdroidserver/metadata.py

@@ -189,6 +189,7 @@ fieldtypes = {
     'MaintainerNotes': TYPE_MULTILINE,
     'Categories': TYPE_LIST,
     'AntiFeatures': TYPE_STRINGMAP,
+    'RequiresRoot': TYPE_BOOL,
     'AllowedAPKSigningKeys': TYPE_LIST,
     'Builds': TYPE_BUILD,
     'VercodeOperation': TYPE_LIST,

tests/update.TestCase

@@ -1433,7 +1433,7 @@ class UpdateTest(unittest.TestCase):
                         'NoSourceSince': '',
                         'Repo': '',
                         'RepoType': '',
-                        'RequiresRoot': '',
+                        'RequiresRoot': None,
                         'SourceCode': '',
                         'Summary': 'rocks.janicerand',
                         'Translation': '',