feat: Update to OPA v1.2.0 (#373)

Regorus now defaults to rego v1. `import rego.v1` is no longer needed.
Additionally, `future` keywords are automatically imported.

See
https://www.openpolicyagent.org/docs/latest/v0-upgrade/#changes-to-rego-in-opa-v10
to understand the differences between rego v1 and v0.

BREAKING CHANGE:

v0 style policies will error out by default. To enable v0 behavior, call engine.set_rego_v0(true) before
loading policies.

Signed-off-by: Anand Krishnamoorthi <anakrish@microsoft.com>

src/tests/interpreter/mod.rs

@@ -141,6 +141,7 @@ pub fn eval_file(
     strict: bool,
 ) -> Result<(Vec<Value>, Vec<String>)> {
     let mut engine: Engine = Engine::new();
+    engine.set_rego_v0(true);
     engine.set_strict_builtin_errors(strict);
     engine.set_gather_prints(true);