Update dependencies. (rust-lang#1211)

* Removed the itertools dependency

* Removed an unused feature flag

* Stubbed out a toml_query replacement

* Update dependencies.

* Bump env_logger.

* Use warp instead of iron for http server.

Iron does not appear to be maintained anymore. warp/hyper seems to be
reasonably maintained. Unfortunately this takes a few seconds more
to compile, but shouldn't be too bad.

One benefit is that there is no longer a need for a separate websocket
port, which makes it easier to run multiple servers at once.

* Update pulldown-cmark to 0.7

* Switch from error-chain to anyhow.

* Bump MSRV to 1.39.

* Update elasticlunr-rs.

Co-authored-by: Michael Bryan <michaelfbryan@gmail.com>

.github/workflows/main.yml

@@ -31,7 +31,7 @@ jobs:
             rust: stable
           - build: msrv
             os: ubuntu-latest
-            rust: 1.35.0
+            rust: 1.39.0
     steps:
     - uses: actions/checkout@master
     - name: Install Rust