authorize: implement allowed_idp_claims (#1542)

* add arbitrary claims to session

* add support for maps

* update flattened claims

* fix eol

* fix trailing whitespace

* fix tests

pkg/protoutil/struct_test.go

@@ -0,0 +1,39 @@
+package protoutil
+
+import (
+	"testing"
+
+	"github.com/pomerium/pomerium/internal/testutil"
+)
+
+func TestToValue(t *testing.T) {
+	testCases := []struct {
+		name   string
+		value  interface{}
+		expect string
+	}{
+		{"bool", true, "true"},
+		{"float64", 1.2345, "1.2345"},
+		{"float32", float32(0.4000000059604645), "0.4000000059604645"},
+		{"int", int(1), "1"},
+		{"int8", int8(1), "1"},
+		{"int16", int16(1), "1"},
+		{"int32", int32(1), "1"},
+		{"int64", int64(1), "1"},
+		{"string", "test", `"test"`},
+		{"uint", uint(1), "1"},
+		{"uint8", uint8(1), "1"},
+		{"uint16", uint16(1), "1"},
+		{"uint32", uint32(1), "1"},
+		{"uint64", uint64(1), "1"},
+		{"[]interface{}", []interface{}{1, 2, 3, 4}, `[1,2,3,4]`},
+		{"map[string]interface{}", map[string]interface{}{"k1": "v1", "k2": "v2"}, `{"k1":"v1","k2":"v2"}`},
+	}
+	for _, tc := range testCases {
+		tc := tc
+		t.Run(tc.name, func(t *testing.T) {
+			actual := ToStruct(tc.value)
+			testutil.AssertProtoJSONEqual(t, tc.expect, actual)
+		})
+	}
+}