doc(readme): Add docker usage doc (#3103)

* doc(readme): Add docker usage doc

* fix heading size

Co-authored-by: itchyny <itchyny@cybozu.co.jp>

README.md

@@ -17,6 +17,17 @@ Download the latest releases from the [GitHub release page](https://github.com/j
 
 Pull the [jq image](https://github.com/jqlang/jq/pkgs/container/jq) to start quickly with Docker.
 
+
+#### Run with Docker
+##### Example: Extracting the version from a `package.json` file
+```bash
+docker run --rm -i ghcr.io/jqlang/jq:latest < package.json '.version'
+```
+##### Example: Extracting the version from a `package.json` file with a mounted volume
+```bash
+docker run --rm -i -v "${PWD}":/pwd -w /pwd ghcr.io/jqlang/jq:latest '.version' package.json
+```
+
 ### Building from source
 
 #### Dependencies