build: fix indentation in tests/meson.build

The rest of the file uses tabs, not spaces.

Signed-off-by: Simon Ser <contact@emersion.fr>

tests/meson.build

@@ -11,10 +11,10 @@ foreach protocol_file : protocol_files
 	protocol_path = join_paths(wayland_protocols_srcdir, protocol_file)
 	test_name = 'scan-@0@'.format(protocol_file.underscorify())
 	test(test_name, prog_scan_sh,
-	     args: protocol_path,
-	     env: [
-		     'SCANNER=@0@'.format(prog_scanner.path()),
-	     ]
+		args: protocol_path,
+		env: [
+			'SCANNER=@0@'.format(prog_scanner.path()),
+		]
 	)
 endforeach