protoc-gen-swagger: Update internal mapping for boolean type (grpc-ecosystem#1466)

Fixes grpc-ecosystem#1463

Author: ozraza

examples/internal/proto/examplepb/wrappers.swagger.json

@@ -50,8 +50,7 @@
           "200": {
             "description": "A successful response.",
             "schema": {
-              "type": "boolean",
-              "format": "boolean"
+              "type": "boolean"
             }
           },
           "default": {
@@ -67,8 +66,7 @@
             "in": "body",
             "required": true,
             "schema": {
-              "type": "boolean",
-              "format": "boolean"
+              "type": "boolean"
             }
           }
         ],
@@ -403,9 +401,8 @@
           "type": "number",
           "format": "double"
         },
-        "boolValue": {
-          "type": "boolean",
-          "format": "boolean"
+        "bool_value": {
+          "type": "boolean"
         },
         "uint32Value": {
           "type": "integer",

protoc-gen-openapiv2/internal/genopenapi/template.go

@@ -65,7 +65,6 @@ var wktSchemas = map[string]schemaCore{
 	},
 	".google.protobuf.BoolValue": {
 		Type:   "boolean",
-		Format: "boolean",
 	},
 	".google.protobuf.Empty": {},
 	".google.protobuf.Struct": {

protoc-gen-openapiv2/internal/genopenapi/template_test.go

@@ -2111,7 +2111,6 @@ func TestSchemaOfField(t *testing.T) {
 			refs: make(refMap),
 			expected: schemaCore{
 				Type:   "boolean",
-				Format: "boolean",
 			},
 		},
 		{