Fix link to ProxyAdmin in docs (#699)

* fix link to ProxyAdmin in docs

* Fix link to ProxyAdmin in versioned docs

packages/docs/docs/docs/new_2.2.md

@@ -11,7 +11,7 @@ As of version 2.2, ZeppelinOS projects use at least one contract for their on-ch
 
 However, the [transparent proxy pattern](https://docs.zeppelinos.org/docs/pattern.html#transparent-proxies-and-function-clashes) caused some confusion when interacting with proxies. Basically, you would get errors whenever you tried to interact with the proxy of a contract from the account that created the proxy.
 
-To solve this, ZeppelinOS 2.2 introduces the [ProxyAdmin](https://github.com/zeppelinos/zos/blob/v2.0.0/packages/lib/contracts/upgradeability/ProxyAdmin.sol) contract, which basically becomes the admin of all the proxies you create, and allows you to interact with them normally from any account. Yes, this means that regular ZeppelinOS 2.2 projects will have some on-chain architecture around them, but it is minimal, and exists with the sole purpose of making your life easier.
+To solve this, ZeppelinOS 2.2 introduces the [ProxyAdmin](https://github.com/zeppelinos/zos/blob/v2.2.0/packages/lib/contracts/upgradeability/ProxyAdmin.sol) contract, which basically becomes the admin of all the proxies you create, and allows you to interact with them normally from any account. Yes, this means that regular ZeppelinOS 2.2 projects will have some on-chain architecture around them, but it is minimal, and exists with the sole purpose of making your life easier.
 
 ## Migrating from ZeppelinOS 2.0 or 2.1 to ZeppelinOS 2.2
 

packages/docs/docs/website/versioned_docs/version-2.2.0/new_2.2.md

@@ -12,7 +12,7 @@ As of version 2.2, ZeppelinOS projects use at least one contract for their on-ch
 
 However, the [transparent proxy pattern](https://docs.zeppelinos.org/docs/pattern.html#transparent-proxies-and-function-clashes) caused some confusion when interacting with proxies. Basically, you would get errors whenever you tried to interact with the proxy of a contract from the account that created the proxy.
 
-To solve this, ZeppelinOS 2.2 introduces the [ProxyAdmin](https://github.com/zeppelinos/zos/blob/v2.0.0/packages/lib/contracts/upgradeability/ProxyAdmin.sol) contract, which basically becomes the admin of all the proxies you create, and allows you to interact with them normally from any account. Yes, this means that regular ZeppelinOS 2.2 projects will have some on-chain architecture around them, but it is minimal, and exists with the sole purpose of making your life easier.
+To solve this, ZeppelinOS 2.2 introduces the [ProxyAdmin](https://github.com/zeppelinos/zos/blob/v2.2.0/packages/lib/contracts/upgradeability/ProxyAdmin.sol) contract, which basically becomes the admin of all the proxies you create, and allows you to interact with them normally from any account. Yes, this means that regular ZeppelinOS 2.2 projects will have some on-chain architecture around them, but it is minimal, and exists with the sole purpose of making your life easier.
 
 ## Migrating from ZeppelinOS 2.0 or 2.1 to ZeppelinOS 2.2