A few Docker instructions (like ARG, ENV, LABEL) may contain key-value pairs in form of
<key>=<value>. The equal sign should not be followed by a space. The space before the equal sign may lead to unintended
behavior. This is critical, especially for multiple key-value pairs, e.g. key1 = value1 key2 = value2, will lead to the key
key1 with the value = value1 key2 = value2. In most cases it is unintended.
