fix: support - as an argument value (#70)

src/parse.ts

@@ -130,7 +130,7 @@ export class Parser<T extends ParserInput, TFlags extends OutputFlags<T['flags']
     let parsingFlags = true
     while (this.argv.length) {
       const input = this.argv.shift() as string
-      if (parsingFlags && input.startsWith('-')) {
+      if (parsingFlags && input.startsWith('-') && input !== '-') {
         // attempt to parse as arg
         if (this.input['--'] !== false && input === '--') {
           parsingFlags = false

test/parse.test.ts

@@ -195,6 +195,13 @@ See more help with --help`)
         })
         expect(out.argv).to.deep.equal(['--foo'])
       })
+
+      it('parses - as an arg', () => {
+        const out = parse(['-'], {
+          args: [{name: 'myarg'}],
+        })
+        expect(out.argv).to.deep.equal(['-'])
+      })
     })
 
     describe('args - no args passed in, with defaults', () => {