Fix
* **dependencies:** Bringing dependencies to most current versions to fix security issue with urllib3 ([`e38d555`](https://github.com/PTB-PSt1/time-series-metadata/commit/e38d555a02634bb5fff47ebc4cc60f609f5ee7bd))
Documentation
* **quantities:** Correct documentation on _quantities_ property ([`1fb7c19`](https://github.com/PTB-PSt1/time-series-metadata/commit/1fb7c196f96d956ea18686378737e48f15afadd3))
* **README:** Correct and extend introduction section in _README.md_ ([`f6207ea`](https://github.com/PTB-PSt1/time-series-metadata/commit/f6207eafac98e5e74c7748f19ce4a2f2c65e0208))
* **get_quantity:** Correct docstring ([`8e3b699`](https://github.com/PTB-PSt1/time-series-metadata/commit/8e3b699d0a92ba6d0d9358d1962037fc2eda2ef2))
* **README:** Add badges to _README.md_ ([`4515084`](https://github.com/PTB-PSt1/time-series-metadata/commit/4515084739a889ec9f573dd8546a06742b0faf7d))