FIX: links update (#494)

* FIX: links update

* FIX: collab build

Author: mmcky

.github/workflows/collab.yml

@@ -11,10 +11,11 @@ jobs:
         with:
           ref: ${{ github.event.pull_request.head.sha }}
       # Install build software
-      - name: Install Build Software & LaTeX (kalman_2)
+      - name: Install Build Software & LaTeX
         shell: bash -l {0}
         run: |
           pip install jupyter-book==1.0.3 quantecon-book-theme==0.8.2 sphinx-tojupyter==0.3.0 sphinxext-rediraffe==0.2.7 sphinxcontrib-youtube==1.3.0 sphinx-togglebutton==0.3.2 arviz sphinx-proof sphinx-exercise sphinx-reredirects
+          apt-get update
           apt-get install dvipng texlive texlive-latex-extra texlive-fonts-recommended cm-super    
       - name: Check nvidia drivers
         shell: bash -l {0}

lectures/egm_policy_iter.md

@@ -35,7 +35,7 @@ We found time iteration to be significantly more accurate and efficient.
 
 In this lecture, we'll look at a clever twist on time iteration called the **endogenous grid method** (EGM).
 
-EGM is a numerical method for implementing policy iteration invented by [Chris Carroll](http://www.econ2.jhu.edu/people/ccarroll/).
+EGM is a numerical method for implementing policy iteration invented by [Chris Carroll](https://econ.jhu.edu/directory/christopher-carroll/).
 
 The original reference is {cite}`Carroll2006`.