Fix links to labels and their shields

* Fix links
* Fix shields.io API link

CONTRIBUTING.md

@@ -43,15 +43,15 @@ The current list of labels are [here][link_labels] and include:
 
 <br>
 
-* [![no-code](https://img.shields.io/badge/-no-code-207de5.svg)][link_nocode] These issues don't require any coding knowledge.
+* [![no-code](https://img.shields.io/badge/-no--code-207de5.svg)][link_nocode] These issues don't require any coding knowledge.
 
     If you're looking to contribute but aren't very confident in your coding skills these issues are a great place to start.
 
     All issues with the no code label are suggesting documentation tasks, or asking for feedback or suggestions.
 
 <br>
 
-* [![good-first-bug](https://img.shields.io/badge/-good-first-bug-5319e7.svg)][link_goodfirstbug] These issues contain a task that anyone with any level of experience can help with.
+* [![good-first-bug](https://img.shields.io/badge/-good--first--bug-5319e7.svg)][link_goodfirstbug] These issues contain a task that anyone with any level of experience can help with.
 
     A major goal of the project is to have as many people as possible complete their very first [pull request][link_pullrequest] on one of these issues. They will always have explicit information on who to contact to help you through the process.
 
@@ -61,23 +61,23 @@ The current list of labels are [here][link_labels] and include:
 
 <br>
 
-* [![help-wanted](https://img.shields.io/badge/-help-wanted-159818.svg)][link_helpwanted] These issues contain a task that a member of the team has determined we need additional help with.
+* [![help-wanted](https://img.shields.io/badge/-help--wanted-159818.svg)][link_helpwanted] These issues contain a task that a member of the team has determined we need additional help with.
 
     If you have particular skills then consider reading through these issues as they are a great place to offer your expertise.
 
     If you aren't sure what to offer, you could also recommend issues to your friends/colleagues who may be able to help.
 
 <br>
 
-* [![bug](https://img.shields.io/badge/-bug-fc2929.svg)][link_bugs] These issues point to problems in the project.
+* [![bug](https://img.shields.io/badge/-bug-fc2929.svg)][link_bug] These issues point to problems in the project.
 
     If you find a bug, please give as much detail as possible in your issue.
 
     If you experience the same bug as one already listed, please add any additional information that you have as a comment.
 
 <br>
 
-* [![request](https://img.shields.io/badge/-request-fbca04.svg)][link_requests] These issues are asking for features (or anything else) to be added to the project.
+* [![request](https://img.shields.io/badge/-request-fbca04.svg)][link_request] These issues are asking for features (or anything else) to be added to the project.
 
     If you have a good idea and would like to see it implemented in the Brain Networks in Python project please open a new issue and add in as much detail as possible.