Allow libloading v0.7 and v0.8 (#69)

Author: daxpedda

Cargo.toml

@@ -16,7 +16,8 @@ documentation = "https://docs.rs/hassle-rs"
 [dependencies]
 bitflags = "2"
 com = { version = "0.6", features = ["production"] }
-libloading = "0.8"
+# libloading 0.8 switches from `winapi` to `windows-sys`; permit either
+libloading = ">=0.7,<0.9"
 thiserror = "1.0.2"
 widestring = "1"