Set fr_CA.ISO-8859-1 explicitly, just in case

Author: aitap

.github/workflows/R-CMD-check-occasional.yaml

@@ -22,7 +22,7 @@ jobs:
                  # Multibyte characters: Mandarin
                  'zh_CN.utf8',
                  # Encoding: non-UTF-8 locales for French, Mandarin, and Russian
-                 'fr_CA', 'zh_CN.GB18030', 'ru_RU.KOI8-R', # fr_CA is implicitly 'ISO-8859-1'
+                 'fr_CA.ISO-8859-1', 'zh_CN.GB18030', 'ru_RU.KOI8-R',
                  # Collate order (#3502, see also #7837): Latvian, Azeri, Hungarian, Faroese, Albanian
                  'lv_LV.utf8', 'az_AZ.utf8', 'hu_HU.utf8', 'fo_FO.utf8', 'sq_MK.utf8',
                  # Local time formatting (for R bug #19117)