chore: add install lines to makefile (#291)

Part of [this
fix](https://github.com/semgrep/semgrep-proprietary/pull/2225) for a
sync to OSS that broke.

- [x] I ran `make setup && make` to update the generated code after
editing a `.atd` file (TODO: have a CI check)
- [x] I made sure we're still backward compatible with old versions of
the CLI.
For example, the Semgrep backend need to still be able to *consume* data
generated
	  by Semgrep 1.17.0.
See
https://atd.readthedocs.io/en/latest/atdgen-tutorial.html#smooth-protocol-upgrades

Makefile

@@ -76,8 +76,19 @@ clean:
 setup:
 	# Please install check-jsonschema (Python tool) if this fails:
 	check-jsonschema --version
-	opam update
-	opam install --deps-only .
+	opam update -y
+	opam install -y --deps-only ./dev.opam
+
+.PHONY: setup-ALPINE
+setup-ALPINE: setup-PYTHON
+
+.PHONY: setup-MACOS
+setup-MACOS:
+	brew install check-jsonschema
+
+.PHONY: setup-PYTHON
+setup-PYTHON:
+	pip install check-jsonschema
 
 # The tests require semgrep-core, among other things.
 #