test fixture: change wkg.toml author to authors field

Author: pchickey

crates/wkg/tests/fixtures/wasi-http/wkg.toml

@@ -1,5 +1,5 @@
 [metadata]
-author = "WasmPkg <wasm-pkg@bytecodealliance.org>"
+authors = "WasmPkg <wasm-pkg@bytecodealliance.org>"
 description = "WASI HTTP interface"
 license = "Apache-2.0"
 source = "https://github.com/bytecodealliance/wasm-pkg-tools"