Version 0.61.0

[thiago]

Version 0.61.0

Highlights:

• Support for date ranges in st.date_picker. See docs for more info, but the TLDR is: just pass a list/tuple as the default date and it will be interpreted as a range.
• You can now choose whether st.echo prints the code above or below the output of the echoed
  block. To learn more, refer to the code_location argument in the docs.
• Improved @st.cache support for Keras models and Tensorflow saved_models.