Update libzip on macos

We need libzip 1.7.1, because libzip 1.7.0 is broken.

Closes GH-5737.

Author: nikic

azure/macos/brew.yml

@@ -2,6 +2,8 @@ parameters:
   packages: ''
 
 steps:
+  - script: brew update
+    displayName: 'Update Homebrew'
   - script: |
       brew install pkg-config \
                    autoconf \
@@ -23,11 +25,12 @@ steps:
                    zlib \
                    t1lib \
                    gd \
-                   libzip \
                    gmp \
                    tidyp \
                    libxml2 \
                    libxslt \
                    postgresql
+      # Make sure we don't get broken libzip 1.7.0
+      brew upgrade libzip
       brew link icu4c gettext --force
     displayName: 'Install Build Dependencies'