title: How to adjust the ticks and label size of a pandas plot with secondary_y
body: <p>I have a plot with a left and right y-axis created with <a href="https://pandas.pydata.org/docs/reference/api/pandas.DataFrame.plot.html" rel="nofollow noreferrer"><code>pandas.DataFrame.plot</code></a> and specifying <code>secondary_y=True</code>.</p>
  <p>I want to increase the font sizes of the y-axis tick params, but it seems that only the left side y-axis font size is increasing.</p>
  <pre><code>import pandas as pd
  import numpy as np
  
  # sample dataframe
  sample_length = range(1, 2+1)
  rads = np.arange(0, 2*np.pi, 0.01)
  data = np.array([np.sin(t*rads) for t in sample_length])
  df = pd.DataFrame(data.T, index=pd.Series(rads.tolist(), name='radians'), columns=[f'freq: {i}x' for i in sample_length])
  
  # display(df.head(3))
           freq: 1x  freq: 2x
  radians                    
  0.00     0.000000  0.000000
  0.01     0.010000  0.019999
  0.02     0.019999  0.039989
  
  # plot
  ax1 = df.plot(y='freq: 1x', ylabel='left-Y', figsize=(8, 5))
  df.plot(y='freq: 2x', secondary_y=True, ax=ax1)
  
  ax1.tick_params(axis='both', labelsize=20)
  </code></pre>
  <p><a href="https://i.stack.imgur.com/CLF08.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/CLF08.png" alt="enter image description here" /></a></p>
  <p>What is the way to increase the font size for the right y-axis?</p>