Get GraphQL Access token for Sitecore 10.3

Sitecore.IdentityServer.Host.xml

<!-- NOTE: THIS IS A FRAGMENT. INCLUDE THIS IN Sitecore.IdentityServer.Host.xml, in node /Settings/Sitecore/IdentityServer/Clients -->

<!-- Postman configuration documented here: https://doc.sitecore.com/xp/en/developers/92/sitecore-experience-commerce/bearer-token-authentication.html -->
        <PostmanClient>
          <ClientId>postman-api</ClientId>
          <ClientName>Postman API</ClientName>
          <AccessTokenType>0</AccessTokenType>
          <AllowOfflineAccess>true</AllowOfflineAccess>
          <AlwaysIncludeUserClaimsInIdToken>false</AlwaysIncludeUserClaimsInIdToken>
          <AccessTokenLifetimeInSeconds>3600</AccessTokenLifetimeInSeconds>
          <IdentityTokenLifetimeInSeconds>3600</IdentityTokenLifetimeInSeconds>
          <AllowAccessTokensViaBrowser>true</AllowAccessTokensViaBrowser>
          <RequireConsent>false</RequireConsent>
          <RequireClientSecret>false</RequireClientSecret>
          <AllowedGrantTypes>
            <AllowedGrantType1>password</AllowedGrantType1>
          </AllowedGrantTypes>
          <RedirectUris>
             <RedirectUri1>{AllowedCorsOrigin}/oauth2/callback</RedirectUri1>
          </RedirectUris>
          <PostLogoutRedirectUris>
             <PostLogoutRedirectUri1>{AllowedCorsOrigin}</PostLogoutRedirectUri1>
             </PostLogoutRedirectUris>
          <AllowedCorsOrigins>
              <AllowedCorsOrigins1>https://www.getpostman.com</AllowedCorsOrigins1>
           </AllowedCorsOrigins>
          <AllowedScopes>
            <!-- Scopes documented here: https://doc.sitecore.com/xp/en/developers/103/sitecore-experience-manager/use-bearer-tokens-in-client-applications.html -->
            <AllowedScope1>openid</AllowedScope1>
            <AllowedScope2>sitecore.profile</AllowedScope2>
            <AllowedScope3>sitecore.profile.api</AllowedScope3>
              </AllowedScopes>
           <UpdateAccessTokenClaimsOnRefresh>true</UpdateAccessTokenClaimsOnRefresh>
       </PostmanClient>

Sitecore_GraphQL.postman_collection.json

{
	"info": {
		"_postman_id": "d5816c17-9c4b-4a0f-8b78-beb5ea07e3ae",
		"name": "Sitecore GraphQL",
		"schema": "https://schema.getpostman.com/json/collection/v2.1.0/collection.json",
		"_exporter_id": "0"
	},
	"item": [
		{
			"name": "GetToken",
			"event": [
				{
					"listen": "test",
					"script": {
						"exec": [
							"var jsonData = JSON.parse(responseBody);",
							"",
							"postman.setGlobalVariable(\"SitecoreIdToken\", \"Bearer \" + jsonData.access_token);",
							""
						],
						"type": "text/javascript"
					}
				}
			],
			"request": {
				"method": "POST",
				"header": [
					{
						"key": "Content-Type",
						"value": "application/x-www-form-urlencoded"
					},
					{
						"key": "Accept",
						"value": "application/json"
					}
				],
				"body": {
					"mode": "urlencoded",
					"urlencoded": [
						{
							"key": "password",
							"value": "{{SitecoreIdServerPassword}}",
							"type": "text"
						},
						{
							"key": "grant_type",
							"value": "password",
							"type": "text"
						},
						{
							"key": "username",
							"value": "{{SitecoreIdServerUserName}}",
							"type": "text"
						},
						{
							"key": "client_id",
							"value": "postman-api",
							"type": "text"
						},
						{
							"key": "scope",
							"value": "openid sitecore.profile sitecore.profile.api",
							"type": "text"
						}
					]
				},
				"url": {
					"raw": "{{SitecoreIdServerHost}}/connect/token",
					"host": [
						"{{SitecoreIdServerHost}}"
					],
					"path": [
						"connect",
						"token"
					]
				}
			},
			"response": []
		}
	],
	"event": [
		{
			"listen": "prerequest",
			"script": {
				"type": "text/javascript",
				"exec": [
					""
				]
			}
		},
		{
			"listen": "test",
			"script": {
				"type": "text/javascript",
				"exec": [
					""
				]
			}
		}
	],
	"variable": [
		{
			"key": "SitecoreIdServerHost",
			"value": "https://xp0identityserver.dev.local",
			"type": "string"
		},
		{
			"key": "SitecoreIdServerUserName",
			"value": "sitecore\\admin",
			"type": "string"
		},
		{
			"key": "SitecoreIdServerPassword",
			"value": "b",
			"type": "string"
		}
	]
}