Pin unordered-containers due to internal module change

Author: bergmark

build-constraints/lts-24-build-constraints.yaml

@@ -726,7 +726,7 @@ packages:
         - bsb-http-chunked ^>= 0.0.0.4
         - hspec-parsec ^>= 0
         - checkers ^>= 0.6.0
-        - unordered-containers ^>= 0.2.20
+        - unordered-containers == 0.2.20.1
         - prettyprinter ^>= 1.7.1
         - prettyprinter-ansi-terminal ^>= 1.1.3
         - prettyprinter-compat-wl-pprint ^>= 1.0.1