ci: prep devtoolset 9 with SCL repo

.github/workflows/gen_centos7.yml

@@ -23,6 +23,9 @@ jobs:
     runs-on: "ubuntu-latest"
     container: "centos:7"
     steps:
+    - name: "Install SCL"
+      shell: bash
+      run: "yum install -y centos-release-scl-rh"
     - name: "Update compiler"
       shell: bash
       run: "yum install -y devtoolset-9-gcc devtoolset-9-gcc-c++"

.github/workflows/gen_centos7_continuous.yml

@@ -25,6 +25,13 @@ jobs:
     runs-on: "ubuntu-latest"
     container: "centos:7"
     steps:
+    - name: "Install SCL"
+      shell: bash
+      run: |
+            export BUILD_REASON=Schedule
+            yum install -y centos-release-scl-rh
+            
+
     - name: "Update compiler"
       shell: bash
       run: |

.github/workflows/gen_centos7_tag.yml

@@ -14,6 +14,9 @@ jobs:
     runs-on: "ubuntu-latest"
     container: "centos:7"
     steps:
+    - name: "Install SCL"
+      shell: bash
+      run: "yum install -y centos-release-scl-rh"
     - name: "Update compiler"
       shell: bash
       run: "yum install -y devtoolset-9-gcc devtoolset-9-gcc-c++"

ci/generate-workflows.py

@@ -155,6 +155,12 @@ class Target(object):
     def install_newer_compiler(self):
         steps = []
         if self.name == "centos7":
+            steps.append(
+                RunStep(
+                    "Install SCL",
+                    "yum install -y centos-release-scl-rh",
+                )
+            )
             steps.append(
                 RunStep(
                     "Update compiler",