[ci-bitrise] Fix apikey.json generation to escape multi-line PEM content

ASC_KEY_CONTENT is the raw .p8 private key, which contains literal
newlines. The heredoc interpolated it straight into a JSON string,
producing invalid JSON (JSON::ParserError in get_provisioning_profile).
Build the file with Ruby's JSON encoder instead so newlines are escaped
correctly. Verified locally against a realistic multi-line PEM value.

bitrise.yml

@@ -43,9 +43,18 @@ workflows:
           inputs:
             - content: |
                 echo "DEVELOPMENT_TEAM = $DEVELOPMENT_TEAM" >> "$BITRISE_SOURCE_DIR/Darwin/fastlane/AppStore.xcconfig"
-                cat > "$BITRISE_SOURCE_DIR/Darwin/fastlane/apikey.json" <<EOF
+                # ASC_KEY_CONTENT is the raw multi-line .p8 PEM content — build
-                {"key_id":"$ASC_KEY_ID","issuer_id":"$ASC_ISSUER_ID","key":"$ASC_KEY_CONTENT","in_house":false}
+                # the JSON with Ruby's encoder so its embedded newlines get
-                EOF
+                # escaped correctly instead of breaking the JSON string.
+                export APIKEY_PATH="$BITRISE_SOURCE_DIR/Darwin/fastlane/apikey.json"
+                ruby -rjson -e '
+                  File.write(ENV["APIKEY_PATH"], JSON.generate({
+                    "key_id" => ENV["ASC_KEY_ID"],
+                    "issuer_id" => ENV["ASC_ISSUER_ID"],
+                    "key" => ENV["ASC_KEY_CONTENT"],
+                    "in_house" => false
+                  }))
+                '
       - fastlane@3:
           inputs:
             - lane: beta
@@ -77,9 +86,18 @@ workflows:
           inputs:
             - content: |
                 echo "DEVELOPMENT_TEAM = $DEVELOPMENT_TEAM" >> "$BITRISE_SOURCE_DIR/Darwin/fastlane/AppStore.xcconfig"
-                cat > "$BITRISE_SOURCE_DIR/Darwin/fastlane/apikey.json" <<EOF
+                # ASC_KEY_CONTENT is the raw multi-line .p8 PEM content — build
-                {"key_id":"$ASC_KEY_ID","issuer_id":"$ASC_ISSUER_ID","key":"$ASC_KEY_CONTENT","in_house":false}
+                # the JSON with Ruby's encoder so its embedded newlines get
-                EOF
+                # escaped correctly instead of breaking the JSON string.
+                export APIKEY_PATH="$BITRISE_SOURCE_DIR/Darwin/fastlane/apikey.json"
+                ruby -rjson -e '
+                  File.write(ENV["APIKEY_PATH"], JSON.generate({
+                    "key_id" => ENV["ASC_KEY_ID"],
+                    "issuer_id" => ENV["ASC_ISSUER_ID"],
+                    "key" => ENV["ASC_KEY_CONTENT"],
+                    "in_house" => false
+                  }))
+                '
       - fastlane@3:
           inputs:
             - lane: release