Make update_version.sh work with BSD grep and sed

Read the version with sed instead of grep -P, use sed -i.bak so the
in-place edit works with both GNU and BSD sed, and exit if the version
cannot be read.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

Author: const-cloudinary

tools/update_version.sh

@@ -1,15 +1,19 @@
 #!/usr/bin/env bash
 new_version=$1
 
-current_version=`grep -oP "(?<=VERSION \= \")([0-9.]+)(?=\")" cloudinary-core/src/main/java/com/cloudinary/Cloudinary.java`
+current_version=`sed -n 's/.*VERSION = "\([0-9.]*\)".*/\1/p' cloudinary-core/src/main/java/com/cloudinary/Cloudinary.java`
+if [ -z "$current_version" ]; then
+    echo "Could not read VERSION from cloudinary-core/src/main/java/com/cloudinary/Cloudinary.java"
+    exit 1
+fi
 current_version_re=${current_version//./\\.}
 echo "Current version is $current_version"
 if [ -n "$new_version" ]; then
     echo "New version will be $new_version"
     echo "Pattern used: $current_version_re"
-    sed -e "s/${current_version_re}/${new_version}/g" -i "" cloudinary-core/src/main/java/com/cloudinary/Cloudinary.java
-    sed -e "s/${current_version_re}/${new_version}/g" -i "" README.md
-    sed -e "s/${current_version_re}/${new_version}/g" -i "" gradle.properties
+    for file in cloudinary-core/src/main/java/com/cloudinary/Cloudinary.java README.md gradle.properties; do
+        sed -i.bak -e "s/${current_version_re}/${new_version}/g" "$file" && rm "$file.bak"
+    done
     git changelog -t $new_version
 else
     echo "Usage: $0 <new version>"