Pin libflate <1.3.0

sile/libflate@aba8290
derives default on enum, which was not stabilized until 1.62
(rust-lang/rust#94457)

This can be relaxed when MSRV is at least 1.62

Cargo.toml

@@ -26,7 +26,14 @@ tag-message = "dkregistry v{{version}}"
 base64 = "0.13"
 futures = "0.3"
 http = "0.2"
-libflate = "1.0"
+
+# Pin libflate <1.3.0
+# https://github.com/sile/libflate/commit/aba829043f8a2d527b6c4984034fbe5e7adb0da6
+# derives default on enum, which was not stabilized until 1.62
+# (https://github.com/rust-lang/rust/pull/94457)
+# This can be relaxed when MSRV is at least 1.62
+libflate = "<1.3.0"
+
 log = "0.4"
 mime = "0.3"
 regex = "^1.1.0"