fix(doctor): check for python3 instead of python

Author: rigor789

package.json

@@ -1,7 +1,7 @@
 {
   "name": "nativescript",
   "preferGlobal": true,
-  "version": "8.5.0-dev.0",
+  "version": "8.5.0-rc.0",
   "author": "NativeScript <support@nativescript.org>",
   "description": "Command-line interface for building NativeScript projects",
   "bin": {
@@ -57,7 +57,7 @@
     "mobile"
   ],
   "dependencies": {
-    "@nativescript/doctor": "2.0.9",
+    "@nativescript/doctor": "2.0.10",
     "@nativescript/schematics-executor": "0.0.2",
     "@rigor789/resolve-package-path": "^1.0.5",
     "@rigor789/trapezedev-project": "^7.1.0",

packages/doctor/src/doctor.ts

@@ -255,7 +255,7 @@ export class Doctor implements NativeScriptDoctor.IDoctor {
 					infoMessage: "Python installed and configured correctly.",
 					warningMessage: `Couldn't retrieve installed python packages.`,
 					additionalInformation:
-						"We cannot verify your python installation is setup correctly. Please, make sure you have both 'python' and 'pip' installed." +
+						"We cannot verify your python installation is setup correctly. Please, make sure you have both 'python3' and 'pip3' installed." +
 						EOL +
 						`Error while validating Python packages. Error is: ${sysInfoData.pythonInfo.installationErrorMessage}`,
 					platforms: [Constants.IOS_PLATFORM_NAME],

packages/doctor/src/sys-info.ts

@@ -494,7 +494,7 @@ export class SysInfo implements NativeScriptDoctor.ISysInfo {
 			async (): Promise<NativeScriptDoctor.IPythonInfo> => {
 				if (this.hostInfo.isDarwin) {
 					try {
-						await this.childProcess.exec(`python -c "import six"`);
+						await this.childProcess.exec(`python3 -c "import six"`);
 					} catch (error) {
 						// error.code = 1 so the Python is present, but we don't have six.
 						if (error.code === 1) {

packages/doctor/test/sys-info.ts

@@ -113,7 +113,7 @@ function createChildProcessResults(
 		"tns --version": childProcessResult.nativeScriptCliVersion,
 		emulator: { shouldThrowError: false },
 		"which git": childProcessResult.git,
-		'python -c "import six"': childProcessResult.pythonInfo,
+		'python3 -c "import six"': childProcessResult.pythonInfo,
 	};
 }
 
@@ -608,7 +608,7 @@ Java HotSpot(TM) 64-Bit Server VM (build 25.202-b08, mixed mode)`),
 					isInstalled: false,
 					isSixPackageInstalled: false,
 					installationErrorMessage:
-						'This one throws error. (python -c "import six")',
+						'This one throws error. (python3 -c "import six")',
 				});
 			});
 			it("should return {isInstalled: true, isSixPackageInstalled: false} when python is installed but six package is not", async () => {