At any point of time, time period is given by

$$T=2 \pi \sqrt{\frac{m}{k}}$$

Here $m$ is decreasing, so time period $T$ will be decreasing

Since $\omega=\frac{2 \pi}{T}$

Hence as mass leaks, $\omega$ will increase

Now, at any instant

$m g=k x_0$

So, equilibrium length $x_0=\frac{m g}{k}$, where $m$ is decreasing

So, equilibrium length will decrease.

So, amplitude also go on decreasing.