ci: remove any trace of C++14

Following the Google Foundational C++ Support Policy, we require at least c++17 support
ref: https://github.com/google/oss-policies-info/blob/main/foundational-cxx-support-matrix.md

.github/workflows/amd64_linux_bazel.yml

diff --git a/.github/workflows/amd64_linux_bazel.yml b/.github/workflows/amd64_linux_bazel.yml
index 9d305b3..6a95ef2 100644
--- a/.github/workflows/amd64_linux_bazel.yml
+++ b/.github/workflows/amd64_linux_bazel.yml
@@ -14,7 +14,6 @@
       matrix:
         examples: [{name: basic}, {name: embed}]
         cpp: [
-          #{version: 14, flags: "-std=c++14"},
           {version: 17, flags: "-std=c++17"},
           {version: 20, flags: "-std=c++20"},
         ]

.github/workflows/amd64_macos_bazel.yml

diff --git a/.github/workflows/amd64_macos_bazel.yml b/.github/workflows/amd64_macos_bazel.yml
index c643123..dea57b3 100644
--- a/.github/workflows/amd64_macos_bazel.yml
+++ b/.github/workflows/amd64_macos_bazel.yml
@@ -17,7 +17,6 @@
           # {name: embed}, # see: https://github.com/pybind/pybind11_bazel/issues/76
         ]
         cpp: [
-          #{version: 14, flags: "-std=c++14"},
           {version: 17, flags: "-std=c++17"},
           {version: 20, flags: "-std=c++20"},
         ]

.github/workflows/amd64_windows_bazel.yml

diff --git a/.github/workflows/amd64_windows_bazel.yml b/.github/workflows/amd64_windows_bazel.yml
index 13e398a..21f7d93 100644
--- a/.github/workflows/amd64_windows_bazel.yml
+++ b/.github/workflows/amd64_windows_bazel.yml
@@ -14,7 +14,6 @@
       matrix:
         examples: [{name: basic}, {name: embed}]
         cpp: [
-          #{version: 14, flags: "/std:c++14"},
           {version: 17, flags: "/std:c++17"},
           {version: 20, flags: "/std:c++20"},
         ]

.github/workflows/arm64_macos_bazel.yml

diff --git a/.github/workflows/arm64_macos_bazel.yml b/.github/workflows/arm64_macos_bazel.yml
index 10db0f5..0301f9d 100644
--- a/.github/workflows/arm64_macos_bazel.yml
+++ b/.github/workflows/arm64_macos_bazel.yml
@@ -17,7 +17,6 @@
           # {name: embed}, # see: https://github.com/pybind/pybind11_bazel/issues/76
         ]
         cpp: [
-          #{version: 14, flags: "-std=c++14"},
           {version: 17, flags: "-std=c++17"},
           {version: 20, flags: "-std=c++20"},
         ]