[workspace] Upgrade lcm to latest release v1.5.1

[nicolecheetham]

Towards: #22348

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This change is 

[jwnimmer-tri]

+@sammy-tri for both reviews, please.

Please also test on TRI's robots, if necessary.

Reviewed 3 of 3 files at r1, all commit messages.
Reviewable status: 1 unresolved discussion, LGTM missing from assignee sammy-tri(platform)

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tools/workspace/lcm/repository.bzl line 12 at r1 (raw file):

        When updating, the version numbers within the two lcm-*.cmake files in
        this directory must also be updated to match the new version.
        """,

nit Please also add to the advice here that LCM needs to be its own PR, not part of the big one.

[nicolecheetham]

Reviewable status: 1 unresolved discussion, LGTM missing from assignee sammy-tri(platform)

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tools/workspace/lcm/repository.bzl line 12 at r1 (raw file):

Previously, jwnimmer-tri (Jeremy Nimmer) wrote…

nit Please also add to the advice here that LCM needs to be its own PR, not part of the big one.

The upgrade advice has been updated accordingly.

[jwnimmer-tri]

Reviewed 1 of 1 files at r2, all commit messages.
Reviewable status: 1 unresolved discussion, LGTM missing from assignee sammy-tri(platform)

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tools/workspace/lcm/repository.bzl line 12 at r2 (raw file):

        When updating, the version numbers within the two lcm-*.cmake files in
        this directory must also be updated to match the new version. Moreover,
        lcm needs its own pull request separate from the rest of the monthly 

nit Trailing whitespace at end of line. (I imagine the linter is going to yell.)

[nicolecheetham]

Reviewable status: 1 unresolved discussion, LGTM missing from assignee sammy-tri(platform)

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tools/workspace/lcm/repository.bzl line 12 at r2 (raw file):

Previously, jwnimmer-tri (Jeremy Nimmer) wrote…

nit Trailing whitespace at end of line. (I imagine the linter is going to yell.)

Should be removed now

[jwnimmer-tri]

Reviewable status: LGTM missing from assignee sammy-tri(platform)

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tools/workspace/lcm/repository.bzl line 12 at r2 (raw file):

Previously, nicolecheetham (Nicole C.) wrote…

Should be removed now

FYI When posting a "nit" or "BTW" the nominal action on the author side is to resolve the discussion on their own, either by clicking "Resolve" with no comment, or by posting "Done" which automatically resolves the thread, or if writing out a longer reply, to use the other UI element(s) to mark it as resolved. You don't need to wait for or ping the reviewer to return to the discussion -- saying "nit" or "BTW" is the reviewer's way of communicating that they are OK without explicitly closing the loop.

[sammy-tri]

Tested locally.

Reviewed 2 of 3 files at r1, 1 of 1 files at r3, all commit messages.
Reviewable status: complete! all discussions resolved, LGTM from assignee sammy-tri(platform)