feat: Update to opa v0.67.0 (#286)

Implement strings.count builtin

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

src/builtins/strings.rs

@@ -28,6 +28,7 @@ pub fn register(m: &mut builtins::BuiltinsMap<&'static str, builtins::BuiltinFcn
     m.insert("startswith", (startswith, 2));
     m.insert("strings.any_prefix_match", (any_prefix_match, 2));
     m.insert("strings.any_suffix_match", (any_suffix_match, 2));
+    m.insert("strings.count", (strings_count, 2));
     m.insert("strings.replace_n", (replace_n, 2));
     m.insert("strings.reverse", (reverse, 1));
     m.insert("substring", (substring, 3));
@@ -512,6 +513,27 @@ fn any_suffix_match(
     ))
 }
 
+fn strings_count(
+    span: &Span,
+    params: &[Ref<Expr>],
+    args: &[Value],
+    _strict: bool,
+) -> Result<Value> {
+    let name = "strings.count";
+    ensure_args_count(span, name, params, args, 2)?;
+
+    let search = ensure_string(name, &params[0], &args[0])?;
+    let substring = ensure_string(name, &params[0], &args[1])?;
+
+    Ok(Value::from(
+        search
+            .as_bytes()
+            .windows(substring.len())
+            .filter(|&w| w == substring.as_bytes())
+            .count(),
+    ))
+}
+
 fn startswith(span: &Span, params: &[Ref<Expr>], args: &[Value], _strict: bool) -> Result<Value> {
     let name = "startswith";
     ensure_args_count(span, name, params, args, 2)?;