update docs to use flagd binary directly

Signed-off-by: Skye Gill <[email protected]>

tests/integration/README.md

@@ -5,17 +5,15 @@ If you'd like to run them locally, first pull the `test-harness` git submodule
 ```
 git submodule update --init --recursive
 ```
-then build your flagd image
+then build the flagd binary
 ```
-make docker-build
+make build
 ```
-then run your built flagd image
+then run the flagd binary
 ```
-docker run -p 8013:8013 -v $PWD/test-harness/testing-flags.json:/testing-flags.json ghcr.io/open-feature/flagd:latest start -f file:/testing-flags.json
+./flagd start -f file:test-harness/testing-flags.json
 ```
 and finally run
 ```
 make integration-test
 ```
-
-Note: Testing against the flagd binary directly (rather than the docker image) is [currently](https://github.com/open-feature/flagd/issues/313) unstable (dependent on host's OS).