travis: Move the mac deploy script into a bash script.

.travis.yml

@@ -74,12 +74,11 @@ deploy:
         tags: true
         condition: $TRAVIS_OS_NAME = linux
         repo: tantivy-search/tantivy-py
+        python: 3.8
 
     # Deploy for macos using maturin directly
     provider: script
-    script:
-        - maturin list-python
-        - maturin publish --interpreter python3.7 --username __token__ --password $MATURIN_PASSWORD --no-sdist
+    script: "ci/deploy_mac.sh"
     on:
         tags: true
         condition: $TRAVIS_OS_NAME = osx

ci/deploy_mac.sh

@@ -0,0 +1,7 @@
+#!/usr/bin/env bash
+
+maturin publish \
+    --interpreter python3.7 \
+    --username __token__ \
+    --password "$MATURIN_PASSWORD" \
+    --no-sdist