Perform case-insensitive checking when converting booleans from strings

Change-type: patch
Signed-off-by: Cameron Diver <cameron@balena.io>

src/config/types.ts

@@ -19,8 +19,8 @@ export const PermissiveBoolean = new t.Type<boolean, t.TypeOf<PermissiveType>>(
 	(m, c) =>
 		permissiveValue.validate(m, c).chain(v => {
 			switch (typeof v) {
-				case 'boolean':
 				case 'string':
+				case 'boolean':
 				case 'number':
 					const val = checkTruthy(v);
 					if (val == null) {

src/lib/validation.ts

@@ -61,6 +61,9 @@ export function checkString(s: NullableLiteral): string | void {
  * which represents if the input was truthy
  */
 export function checkTruthy(v: string | boolean | number): boolean | void {
+	if (_.isString(v)) {
+		v = v.toLowerCase();
+	}
 	switch (v) {
 		case '1':
 		case 'true':