Pin and upgrade dependencies

This change pins the test-requirements.txt dependencies and upgrades
two packages. PyYAML is upgraded to 5.1 to match Spyglass and openpyxl,
used to read Excel files, is upgraded to 2.6.2. Neither upgrade affects
the behavior of spyglass.

Change-Id: I0383ed56e62f64e2316925d1ba9d241b165ebdde

requirements.txt

@@ -1,4 +1,5 @@
 click==7.0
-PyYAML==3.12
-openpyxl==2.5.4
+PyYAML==5.1.1
+openpyxl==2.6.2
+
 git+https://opendev.org/airship/spyglass.git

setup.py

@@ -25,8 +25,8 @@ setup(
     packages=find_packages(),
     install_requires=[
         'click==7.0',
-        'PyYAML==3.12',
-        'openpyxl==2.5.4',
+        'PyYAML==5.1',
+        'openpyxl==2.6.2',
     ],
     dependency_links=[
         'git+https://opendev.org/airship/spyglass.git',

test-requirements.txt

@@ -2,7 +2,7 @@
 yapf==0.27.0
 
 # Linting
-hacking>=1.1.0,<1.2.0 # Apache-2.0
+hacking==1.1.0
 
 # Security
-bandit>=1.5.0
+bandit==1.6.0