chore: add license checker (#2)

# What 💻

- Adds license checker

# Why ✋

- Required for open sourcing

# Evidence 📷

Include screenshots, screen recordings, or `console` output here
demonstrating that your changes work as intended

<!-- All sections below are optional. You can uncomment any section
applicable to your Pull Request. -->

<!-- # Notes 📝
* Any notes/thoughts that the reviewers should know prior to reviewing
the code? -->

Author: dutterbutter

.github/workflows/ci.yaml

@@ -15,3 +15,14 @@ jobs:
       - name: Status
         run: |
           exit 0
+
+  license-check:
+    name: license-check
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@93cb6efe18208431cddfb8368fd83d5badbf9bfd # v5
+    - uses: EmbarkStudios/cargo-deny-action@76cd80eb775d7bbbd2d80292136d74d39e1b4918 # v2.0.14
+      with:
+        manifest-path: "./tools/mock-server/Cargo.toml"
+        command: check
+        command-arguments: "--hide-inclusion-graph"

tools/mock-server/LICENSE-MIT

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2023 Matter Labs
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

tools/mock-server/deny.toml

@@ -0,0 +1,69 @@
+[graph]
+targets = [
+    "x86_64-unknown-linux-gnu",
+    "aarch64-unknown-linux-gnu",
+    "x86_64-apple-darwin",
+    "aarch64-apple-darwin",
+]
+all-features = false
+no-default-features = false
+
+[output]
+feature-depth = 1
+
+[advisories]
+ignore = [
+]
+
+[licenses]
+allow = [
+    "MIT",
+    "Apache-2.0",
+    "Unlicense",
+    "BSD-2-Clause",
+    "BSD-3-Clause",
+    "BSL-1.0",
+    "Unicode-3.0",    
+]
+exceptions = [
+    # exceptions are in place due to https://github.com/matter-labs/zksync-os
+    # CC0 is a bit unclear about source code: https://tldrlegal.com/license/creative-commons-cc0-1.0-universal
+]
+confidence-threshold = 0.8
+
+[[licenses.clarify]]
+crate = "ring"
+# SPDX considers OpenSSL to encompass both the OpenSSL and SSLeay licenses
+# https://spdx.org/licenses/OpenSSL.html
+# ISC - Both BoringSSL and ring use this for their new files
+# MIT - "Files in third_party/ have their own licenses, as described therein. The MIT
+# license, for third_party/fiat, which, unlike other third_party directories, is
+# compiled into non-test libraries, is included below."
+# OpenSSL - Obviously
+expression = "ISC AND MIT AND OpenSSL"
+license-files = [{ path = "LICENSE", hash = 0xbd0eed23 }]
+
+[licenses.private]
+ignore = false
+registries = []
+
+[bans]
+multiple-versions = "allow"
+wildcards = "allow"
+highlight = "all"
+workspace-default-features = "allow"
+external-default-features = "allow"
+allow = []
+skip = []
+skip-tree = []
+
+[sources]
+unknown-registry = "deny"
+unknown-git = "allow"
+allow-registry = ["https://github.com/rust-lang/crates.io-index"]
+allow-git = []
+
+[sources.allow-org]
+github = []
+gitlab = []
+bitbucket = []