README: use different 1Password icon URL.
README: use different 1Password icon URL.

Co-authored-by: Eric Knibbe <29c2e4fefe47900140d819c5c4413f928c6f7d5f@outlook.com>
MikeMcQuaid/brew,Homebrew/brew,JCount/brew,sjackman/homebrew,nandub/brew,JCount/brew,sjackman/homebrew,claui/brew,JCount/brew,nandub/brew,claui/brew,nandub/brew,claui/brew,Homebrew/brew,sjackman/homebrew,Homebrew/brew,EricFromCanada/brew,MikeMcQuaid/brew,claui/brew,sjackman/homebrew,MikeMcQuaid/brew,EricFromCanada/brew,JCount/brew,nandub/brew,Homebrew/brew,MikeMcQuaid/brew,EricFromCanada/brew,EricFromCanada/brew