feat: 🎸 add example for clojure lein project deps

In Clojure, Lein tool is used to generate template for various projects.
Lein project metadata (including project dependencies) are stored in
prject.clj (in root directory) file. Lein downloads dependencies in
classpath (~/.m2/repository). So here I am caching ~/.m2/repository path
for reusing cache in subsequent builds.

README.md

@@ -79,6 +79,7 @@ Every programming language and framework has its own way of caching.
 See [Examples](examples.md) for a list of `actions/cache` implementations for use with:
 
 - [C# - NuGet](./examples.md#c---nuget)
+- [Clojure - Lein Deps](./examples.md#clojure---lein-deps)
 - [D - DUB](./examples.md#d---dub)
 - [Deno](./examples.md#deno)
 - [Elixir - Mix](./examples.md#elixir---mix)

examples.md

@@ -1,6 +1,7 @@
 # Examples
 
 - [C# - NuGet](#c---nuget)
+- [Clojure - Lein Deps](#clojure---lein-deps)
 - [D - DUB](#d---dub)
   - [POSIX](#posix)
   - [Windows](#windows)
@@ -80,6 +81,19 @@ steps:
         ${{ runner.os }}-nuget-
 ```
 
+## Clojure - Lein Deps
+
+```yaml
+- name: Cache lein project dependencies
+  uses: actions/cache@v3
+  with:
+    path: ~/.m2/repository
+    key: ${{ runner.os }}-clojure-${{ hashFiles('**/project.clj') }}
+    restore-keys: |
+      ${{ runner.os }}-clojure
+```
+
+
 ## D - DUB
 
 ### POSIX