Full documentation for using this provider can be found at Jira Documentation
You also need to generate key pair:
mkdir storage/app/keys
openssl genrsa -out storage/app/keys/jira.pem 1024
openssl rsa -in storage/app/keys/jira.pem -pubout -out storage/app/keys/jira.pub
Your key is now in storage/app/keys/jira.pub
And add this to your .env file
JIRA_KEY="yourkey"
JIRA_SECRET="yoursecret"
JIRA_REDIRECT_URI="http://yoursite.com/social/auth/jira"
JIRA_BASE_URI="https://example.atlassian.net"
JIRA_CERT_PATH = "storage/app/keys/jira.pub"