fix for broken link

Author: toppare

Diff for: Chapter2_MorePyMC/Ch2_MorePyMC_PyMC3.ipynb

@@ -246,7 +246,7 @@
     "\n",
     "`some_variable = pm.DiscreteUniform(\"discrete_uni_var\", 0, 4)`\n",
     "\n",
-    "where 0, 4 are the `DiscreteUniform`-specific lower and upper bound on the random variable. The [PyMC3 docs](http://pymc-devs.github.io/pymc3/api.html) contain the specific parameters for stochastic variables. (Or use `??` if you are using IPython!)\n",
+    "where 0, 4 are the `DiscreteUniform`-specific lower and upper bound on the random variable. The [PyMC3 docs](https://docs.pymc.io/en/stable/api.html) contain the specific parameters for stochastic variables. (Or use `??` if you are using IPython!)\n",
     "\n",
     "The `name` attribute is used to retrieve the posterior distribution later in the analysis, so it is best to use a descriptive name. Typically, I use the Python variable's name as the `name`.\n",
     "\n",