Typos on the GraphQLConf banners

[yurishevtsov]

Description

Typo on the GraphQLConf banner on the main page: FRANCISO should be FRANCISCO

Another typo on the conference page (https://graphql.org/conf/): FRANSISCO should be FRANCISCO

Steps to Reproduce

• Navigate to https://graphql.org/ and check the GraphQLConf banner
• Navigate to https://graphql.org/conf/ and check the banner at the top of the page

Expected Result

• the banner should read: "SAN FRANCISCO BAY AREA"

Actual Result

• the banner reads:
  • SAN FRANCISO on the main page (https://graphql.org/)
  • SAN FRANSISCO on https://graphql.org/conf/

[yurishevtsov]

Opened a PR to address both typos: #1450