Euler’s method can be applied to approximate the solution of the initial value problem $y^{\prime }\left(t\right)=t+y$, $y\left(0\right)=2$ on the interval $[0,0.3]$ with a uniform grid: $t_0=0$, $t_1=0.1$, $t_2=0.2$, $t_3=0.3$. Find the value of $u_1$ after the first Euler step.