Fix issues in mustache script

.github/scripts/expand_mustache.sh

@@ -1,18 +1,23 @@
+#!/usr/bin/env bash
 echo '{"array": ["dummy"], "variable": "dummy"}' > .mustache_config.json
-for yamlfile in $(find . -name "*.yml" -o -name "*.yaml"); do
+
+while read -r -d '' yamlfile; do
 
     filename=$(basename -- "$yamlfile")
-    extension="${filename##*.}"
     filename="${filename%.*}"
     test_config=".github/resources/$filename.config.json"
 
     if [ -e "$test_config" ]; then
-        mustache $test_config $yamlfile > $yamlfile
+        mustache "$test_config" "$yamlfile" | sponge "$yamlfile"
     else
-        sed "s|{{\([/#]\)[^}]*}}|{{\1array}}|g" $yamlfile > expanded.tmp  # replace mustache arrays
-        sed -i "s|{{[^#/].\{1,\}}}|{{variable}}|g" expanded.tmp           # replace mustache variables
-        mustache .mustache_config.json expanded.tmp > $yamlfile           # perform mustache expansion overwriting original file
+        # replace mustache arrays
+        sed "s|{{\([/#]\)[^}]*}}|{{\1array}}|g" "$yamlfile" > expanded.tmp
+        # replace mustache variables
+        sed -i "s|{{[^#/].\{1,\}}}|{{variable}}|g" expanded.tmp
+        # perform mustache expansion overwriting original file
+        mustache .mustache_config.json expanded.tmp > "$yamlfile"
     fi
 
-done
+done < <(find . -name "*.yml" -o -name "*.yaml")
+
 rm expanded.tmp