gh-pages workflow update to remove archived actions-rs (#7380)

## Description

Updated the `github pages` workflow; switch from
`actions-rs/toolchain@v1` to `dtolnay/rust-toolchain@master` for rust
env setup.
Also added the `wasm32-unknown-unknown` target.

Completely removed `actions-rs` actions - since these are now archived.
Inlined the `actions-rs/cargo@v1` to `cargo install` - since the
toolchain/binary is available via `dtolnay/rust-toolchain` action.

## Checklist

- [ ] I have linked to any relevant issues.
- [ ] I have commented my code, particularly in hard-to-understand
areas.
- [ ] I have updated the documentation where relevant (API docs, the
reference, and the Sway book).
- [ ] If my change requires substantial documentation changes, I have
[requested support from the DevRel
team](https://github.com/FuelLabs/devrel-requests/issues/new/choose)
- [ ] I have added tests that prove my fix is effective or that my
feature works.
- [ ] I have added (or requested a maintainer to add) the necessary
`Breaking*` or `New Feature` labels where relevant.
- [ ] I have done my best to ensure that my PR adheres to [the Fuel Labs
Code Review
Standards](https://github.com/FuelLabs/rfcs/blob/master/text/code-standards/external-contributors.md).
- [ ] I have requested a review from the relevant team or maintainers.

---------

Co-authored-by: z <zees-dev@users.noreply.github.com>
Co-authored-by: Joshua Batty <joshpbatty@gmail.com>

Author: zees-dev

.github/workflows/gh-pages.yml

@@ -6,6 +6,10 @@ on:
       - master
     tags:
       - v*
+  workflow_dispatch:
+
+env:
+  RUST_VERSION: 1.86.0
 
 jobs:
   deploy:
@@ -14,15 +18,16 @@ jobs:
       - uses: actions/checkout@v3
 
       - uses: Swatinem/rust-cache@v1
-      - uses: actions-rs/toolchain@v1
+
+      - name: Install toolchain
+        uses: dtolnay/rust-toolchain@master
         with:
-          profile: minimal
-          toolchain: stable
+          toolchain: ${{ env.RUST_VERSION }}
+          targets: wasm32-unknown-unknown
+
       - name: Install Forc
-        uses: actions-rs/cargo@v1
-        with:
-          command: install
-          args: --locked --debug --path ./forc
+        run: cargo install --locked --debug --path ./forc
+
       - name: Install Forc plugins
         run: |
           cargo install --locked --debug --path ./forc-plugins/forc-client
@@ -35,11 +40,9 @@ jobs:
           cargo install --locked --debug --path ./forc-plugins/forc-migrate
           cargo install --locked --debug --path ./forc-plugins/forc-node
           cargo install --locked --debug --path ./forc-plugins/forc-publish
+
       - name: Install mdbook-forc-documenter
-        uses: actions-rs/cargo@v1
-        with:
-          command: install
-          args: --locked --debug --path ./scripts/mdbook-forc-documenter
+        run: cargo install --locked --debug --path ./scripts/mdbook-forc-documenter
 
       - name: Setup mdBook
         uses: peaceiris/actions-mdbook@v1