Update metadata to "Pixel Devs"

[Brian Gershon]

IPFS

• For prod metadata "description" ("Pixel Avatars are a collection..."), change to "Pixel Devs is a collection..."

Contract

• Update token name in contract to be "Pixel Devs" (@briangershon) Not able to change unless we choose to redeploy production.
• Fix "Pixel Avatars" directly in OpenSea metadata (@briangershon)

OpenSEA

• See #98

cc: @rasmuscnielsen @etherinsight @goldzulu