An explicit upper bound for $L(1,\chi )$ when $\chi$ is quadratic

We consider Dirichlet $L$-functions $L(s,\chi )$ where $\chi$ is a non-principal quadratic character to the modulus $q$. We make explicit a result due to Pintz and Stephens by showing that $\mathrm{\mid }L(1,\chi )\mathrm{\mid }\le \frac{1}{2}\log q$ for all $q\ge 2\cdot {10}^{23}$ and $\mathrm{\mid }L(1,\chi )\mathrm{\mid }\le \frac{9}{20}\log q$ for all $q\ge 5\cdot {10}^{50}$.