Add @typescript-eslint/strict-boolean-expressions rule

https://github.com/typescript-eslint/typescript-eslint/blob/master/packages/eslint-plugin/docs/rules/strict-boolean-expressions.md

Author: sindresorhus

index.js

@@ -265,6 +265,12 @@ module.exports = {
 			'error',
 			'always'
 		],
+		'@typescript-eslint/strict-boolean-expressions': [
+			'error',
+			{
+				allowNullable: true
+			}
+		],
 		'@typescript-eslint/triple-slash-reference': [
 			'error',
 			{

package.json

@@ -42,15 +42,15 @@
 		"simple"
 	],
 	"devDependencies": {
-		"@typescript-eslint/eslint-plugin": "^2.2.0",
-		"@typescript-eslint/parser": "^2.2.0",
-		"ava": "^2.3.0",
-		"eslint": "^6.3.0",
+		"@typescript-eslint/eslint-plugin": "^2.3.0",
+		"@typescript-eslint/parser": "^2.3.0",
+		"ava": "^2.4.0",
+		"eslint": "^6.4.0",
 		"temp-write": "^4.0.0",
-		"typescript": "^3.6.2"
+		"typescript": "^3.6.3"
 	},
 	"peerDependencies": {
-		"@typescript-eslint/eslint-plugin": ">=2.2.0",
+		"@typescript-eslint/eslint-plugin": ">=2.3.0",
 		"eslint": ">=5.16.0",
 		"typescript": ">=3.5.3"
 	}