Typo in bold formatting. (aimacode#298)

* Corrected the bad bold formatting.

* Changed Python version locally.

* Reverted back the local environment changes.

Author: sampadsaha5

agents.ipynb

@@ -8,7 +8,7 @@
     "\n",
     "An agent, as defined in 2.1 is anything that can perceive its <b>environment</b> through sensors, and act upon that environment through actuators based on its <b>agent program</b>. This can be a dog, robot, or even you. As long as you can perceive the environment and act on it, you are an agent. This notebook will explain how to implement a simple agent, create an environment, and create a program that helps the agent act on the environment based on its percepts.\n",
     "\n",
-    "Before moving on, review the </b>Agent</b> and </b>Environment</b> classes in <b>[agents.py](https://github.com/aimacode/aima-python/blob/master/agents.py)</b>.\n",
+    "Before moving on, review the <b>Agent</b> and <b>Environment</b> classes in <b>[agents.py](https://github.com/aimacode/aima-python/blob/master/agents.py)</b>.\n",
     "\n",
     "Let's begin by importing all the functions from the agents.py module and creating our first agent - a blind dog."
    ]