pants: Add shellcheck for shell_source(s) targets

This excludes some scripts from shellcheck because they weren't linted
previously. We can clean them up in one or more follow-up PRs and remove
`skip_shellcheck=True` from the relevant BUILD targets to re-enable
shellcheck for those files.

Author: cognifloyd

contrib/core/actions/send_mail/BUILD

@@ -1,3 +1,4 @@
 shell_source(
     source="send_mail",
+    skip_shellcheck=True,
 )

contrib/examples/actions/BUILD

@@ -2,4 +2,5 @@ python_sources()
 
 shell_sources(
     name="shell",
+    skip_shellcheck=True,
 )

contrib/examples/actions/bash_ping/BUILD

@@ -1 +1 @@
-shell_sources()
+shell_sources(skip_shellcheck=True)

contrib/examples/actions/bash_random/BUILD

@@ -1 +1,5 @@
-shell_sources()
+shell_sources(
+    overrides={
+        "random2.sh": {"skip_shellcheck": True},
+    },
+)

contrib/linux/actions/BUILD

@@ -2,4 +2,5 @@ python_sources()
 
 shell_sources(
     name="shell",
+    skip_shellcheck=True,
 )

pants.toml

@@ -15,6 +15,7 @@ backend_packages = [
 
   # shell
   "pants.backend.shell",
+  "pants.backend.shell.lint.shellcheck",
 ]
 # pants ignores files in .gitignore, .*/ directories, /dist/ directory, and __pycache__.
 pants_ignore.add = [

st2actions/bin/BUILD

@@ -4,4 +4,5 @@ python_sources(
 
 shell_sources(
     name="shell",
+    skip_shellcheck=True,
 )

st2common/bin/BUILD

@@ -5,4 +5,5 @@ python_sources(
 shell_sources(
     name="shell",
     sources=["st2ctl", "st2-self-check", "st2-run-pack-tests"],
+    skip_shellcheck=True,
 )

st2common/bin/migrations/v2.1/BUILD

@@ -2,4 +2,5 @@ python_sources()
 
 shell_sources(
     name="shell",
+    skip_shellcheck=True,
 )

st2tests/integration/BUILD

@@ -1,3 +1,4 @@
 shell_sources(
     name="shell",
+    skip_shellcheck=True,
 )