fix(regex): update the path segment regex (#1680)

Author: philibea

.changeset/thin-oranges-return.md

@@ -0,0 +1,5 @@
+---
+'@scaleway/regex': patch
+---
+
+Update pathSegment regex

packages/regex/src/__tests__/index.ts

@@ -969,6 +969,9 @@ describe('@regex', () => {
       ['hello?', false],
       ['hello-world', true],
       ['hello/world', false],
+      ['/', false],
+      ['a', true],
+      ['1', true],
     ])('should match regex %s to be %s', (string, expected) => {
       expect(pathSegment.test(string)).toBe(expected)
     })

packages/regex/src/index.ts

@@ -82,5 +82,5 @@ export const reverseDNS = /^[a-z0-9-]+(\.[a-z0-9-]{1,63})+(\.)$/
 export const dashedIpv4 =
   /(\b25[0-5]|\b2[0-4][0-9]|\b[01]?[0-9][0-9]?)(-(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)){3}/
 
-export const pathSegment = /^[_a-zA-Z0-9][-_.a-zA-Z0-9]*[_a-zA-Z0-9]$/
+export const pathSegment = /^[_a-zA-Z0-9]([-_.a-zA-Z0-9]*[_a-zA-Z0-9])?$/
 export const absolutePath = /^\/(([\w. -]*)[^\s?]\/?)+$/