Add new crate leon-macros that provide template! with identical syntax as runtime parsing (#946)

`leon_macros::template!` can parse template at compile-time.
It accepts a utf-8 string literal and uses `leon` internally to parse it, then generate code that evaluates to `Template<'static>`.

 - Exclude fuzz from crate leon when publishing
 - Impl fn-like proc-macro `leon_macros::template!`
 - Add dep `leon-macros` to binstalk
 - Use `leon_macros::template!` in `binstalk::fetchers::gh_crate_meta::hosting`
 - Add doc for `leon-macros` in `leon`
 - Improve `std::fmt::Display` impl for `leon::ParseError`
 - Fixed broken infra link in leon

Signed-off-by: Jiahao XU <Jiahao_XU@outlook.com>

.github/dependabot.yml

@@ -52,3 +52,7 @@ updates:
     directory: "/crates/leon"
     schedule:
       interval: "daily"
+  - package-ecosystem: "cargo"
+    directory: "/crates/leon-macros"
+    schedule:
+      interval: "daily"

.github/workflows/release-pr.yml

@@ -17,6 +17,7 @@ on:
           - fs-lock
           - normalize-path
           - leon
+          - leon-macros
       version:
         description: Version to release
         required: true