Remove py2 from github actions

Although we haven't removed py2 support yet, it's no longer available in
github actions so it's been consistently failing in recent github action
runs.

Also add `fail-fast: false` to all matrices in github actions.
diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 542e768..8b660bb 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -43,6 +43,7 @@
     strategy:
       matrix:
         os: [ubuntu-20.04, ubuntu-22.04]
+      fail-fast: false
     runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@v3
@@ -84,6 +85,7 @@
         go:
           - '1.19'
           - '1.20'
+      fail-fast: false
     steps:
       - uses: actions/checkout@v3
 
@@ -349,7 +351,9 @@
     runs-on: ubuntu-20.04
     strategy:
       matrix:
-        python-version: ["2.x", "3.x"]
+        python-version:
+          - "3.x"
+      fail-fast: false
     steps:
       - uses: actions/checkout@v3
 
@@ -370,21 +374,11 @@
           python --version
           pip --version
 
-      - name: Python 2.x backport setup
-        if: matrix.python-version == '2.x'
-        run: |
-          python -m pip install --upgrade ipaddress backports.ssl_match_hostname
-
       - name: Run bootstrap
         run: ./bootstrap.sh
 
-      - name: Run configure 2.x
-        if: matrix.python-version == '2.x'
-        run: |
-          ./configure $(echo $CONFIG_ARGS_FOR_LIBS | sed 's/without-python/with-python/')
-
       - name: Run configure 3.x
-        if: matrix.python-version != '2.x'
+        if: matrix.python-version == '3.x'
         run: |
           ./configure $(echo $CONFIG_ARGS_FOR_LIBS | sed 's/without-py3/with-py3/')