Revert introduction of [workspace.dependencies].

This was done in #145740 and #145947. It is causing problems for people
using r-a on anything that uses the rustc-dev rustup package, e.g. Miri,
clippy.

This repository has lots of submodules and subtrees and various
different projects are carved out of pieces of it. It seems like
`[workspace.dependencies]` will just be more trouble than it's worth.

compiler/rustc_fluent_macro/Cargo.toml

@@ -11,8 +11,8 @@ proc-macro = true
 annotate-snippets = "0.11"
 fluent-bundle = "0.16"
 fluent-syntax = "0.12"
-proc-macro2.workspace = true
-quote.workspace = true
+proc-macro2 = "1"
+quote = "1"
 syn = { version = "2", features = ["full"] }
 unic-langid = { version = "0.9.0", features = ["macros"] }
 # tidy-alphabetical-end