public K6Container withScriptVar(String key, String value) {
        scriptVars.put(key, value);
        return self();
    }
Adds a key-value pair for access within test scripts as an environment variable.
@param key   unique identifier for the variable
@param value value of the variable
@return the builder
modules/k6/src/main/java/org/testcontainers/k6/K6Container.java