Fix #28 incorrect links in README

Author: mvandervliet

README.md

@@ -39,7 +39,7 @@ The syntax comes from the [Software Package Data eXchange (SPDX)](https://spdx.o
 
 The bulk of the SPDX standard describes syntax and semantics of XML metadata files.  This package implements two lightweight, plain-text components of that larger standard:
 
-1.  The [license list](https://spdx.org/licenses), a mapping from specific string identifiers, like `Apache-2.0`, to standard form license texts and bolt-on license exceptions.  The [spdx-license-ids](https://www.npmjs.com/package/spdx-exceptions) and [spdx-exceptions](https://www.npmjs.com/package/spdx-license-ids) packages implement the license list.  `spdx-expression-parse` depends on and `require()`s them.
+1.  The [license list](https://spdx.org/licenses), a mapping from specific string identifiers, like `Apache-2.0`, to standard form license texts and bolt-on license exceptions.  The [spdx-license-ids](https://www.npmjs.com/package/spdx-license-ids) and [spdx-exceptions](https://www.npmjs.com/package/spdx-exceptions) packages implement the license list.  `spdx-expression-parse` depends on and `require()`s them.
 
     Any license identifier from the license list is a valid license expression: